NZ759815B2 - Advanced gate drivers for silicon carbide bipolar junction transistors - Google Patents
Advanced gate drivers for silicon carbide bipolar junction transistors Download PDFInfo
- Publication number
- NZ759815B2 NZ759815B2 NZ759815A NZ75981518A NZ759815B2 NZ 759815 B2 NZ759815 B2 NZ 759815B2 NZ 759815 A NZ759815 A NZ 759815A NZ 75981518 A NZ75981518 A NZ 75981518A NZ 759815 B2 NZ759815 B2 NZ 759815B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- gate driver
- voltage
- bjt
- regulator
- driver circuit
- Prior art date
Links
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims description 47
- 229910010271 silicon carbide Inorganic materials 0.000 title claims description 43
- 239000003990 capacitor Substances 0.000 claims abstract description 8
- 238000000034 method Methods 0.000 claims description 22
- 230000001105 regulatory effect Effects 0.000 claims description 10
- 230000000694 effects Effects 0.000 claims description 7
- 230000008569 process Effects 0.000 claims description 4
- 230000001360 synchronised effect Effects 0.000 claims description 4
- 230000036039 immunity Effects 0.000 claims description 3
- 238000012544 monitoring process Methods 0.000 claims description 3
- 230000001276 controlling effect Effects 0.000 claims description 2
- 230000001419 dependent effect Effects 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 6
- 238000012986 modification Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000013459 approach Methods 0.000 description 2
- 239000000872 buffer Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000001143 conditioned effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
Classifications
-
- H01L29/0804—
-
- H01L29/0821—
-
- H01L29/1095—
-
- H01L29/1608—
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/217—Class D power amplifiers; Switching amplifiers
- H03F3/2171—Class D power amplifiers; Switching amplifiers with field-effect devices
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/06—Modifications for ensuring a fully conducting state
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/14—Modifications for compensating variations of physical values, e.g. of temperature
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/60—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being bipolar transistors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
- H03K2217/0027—Measuring means of, e.g. currents through or voltages across the switch
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
- H03K2217/0036—Means reducing energy consumption
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
- H03K2217/0081—Power supply means, e.g. to the switch driver
Abstract
gate driver circuit comprises a sensor, an amplifier, a regulator and a gate driver. The sensor is configured to sense a collector-emitter voltage and includes a first resistor and a second resistor connected in series, a high voltage diode connected between the series connected first and second resistors and a first capacitor connected parallel to the second resistor. The amplifier is configured to amplify a sensor output voltage and includes a non-inverting operational amplifier controlled by means of a plurality of resistors, a voltage follower connected to an output terminal of the non-inverting operational amplifier through a first diode and a third resistor connected across the first diode and the voltage follower. The regulator is configured to regulate a regulator output voltage based on an amplifier voltage. The gate driver is configured to connect/disconnect the regulator output voltage to the base terminal of the BJT. esistors and a first capacitor connected parallel to the second resistor. The amplifier is configured to amplify a sensor output voltage and includes a non-inverting operational amplifier controlled by means of a plurality of resistors, a voltage follower connected to an output terminal of the non-inverting operational amplifier through a first diode and a third resistor connected across the first diode and the voltage follower. The regulator is configured to regulate a regulator output voltage based on an amplifier voltage. The gate driver is configured to connect/disconnect the regulator output voltage to the base terminal of the BJT.
Description
ADVANCED GATE DRIVERS FOR SILICON CARBIDE BIPOLAR JUNCTION
TRANSISTORS
RELATED APPLICATIONS
This application is a Patent Cooperation Treaty application based on
United States Utility Patent Application Serial Number 15/990881 filed May 29, 2018,
and which claims priority from the United States provisional application with Serial
Number 62/520645 filed on June 16, 2017. The disclosures of these applications are
incorporated herein as if set out in full.
BACKGROUND OF THE DISCLOSURE
TECHNICAL FIELD OF THE DISCLOSURE
This invention relates generally to bipolar junction transistors, and more
particularly to an advanced gate driver circuit for silicon carbide (SiC) bipolar junction
transistors (BJTs) with minimum power consumption.
DESCRIPTION OF THE RELATED ART
Power switching devices have shown drastic developments due to
advancements in material science and manufacturing techniques. Among the available
power switching devices, Silicon Carbide Bipolar Junction Transistors (SiC BJTs) have
the lowest specific on-resistance and operate over a wide range of temperatures with
average switching losses. The current gain of SiC BJT is close to 100, which reduces the
base current requirement and hence the driver losses. Moreover, the absence of gateoxide
in SiC BJTs makes the technology suitable for high operating temperatures. However,
BJTs require continuous base current to maintain their on-state. This, necessitates the need
for high power rating drivers which in turn results in higher losses. Moreover, the base
current required at high loads can easily compromise the overall efficiency of the switch
and the driver at light loads if it is not adjusted properly. Therefore, the base driver is a
key component in SiC BJT based converters.
External drive circuits are required to supply the relatively large base
currents that are required by high power BJTs. These drive circuits are used to selectively
provide a current to the base of the BJT that switches the transistor between ON and OFF
states. The base current is determined by the collector current and the DC current gain.
However, the collector current varies within each switching period depending on the
converter topology and the load. In addition, the current gain is also current and
temperature sensitive. Thus, the maximization of the efficiency of the combination of
switch and driver becomes a challenging task.
One of the currently available gate drivers provides a Darlington
configuration with the SiC BJT which increases the DC current gain beyond 3400. This
method reduces the base current requirement to a level where it can be maintained
constant regardless of the converter topology, its load and the temperature, all without
compromising the efficiency of the switch and the driver. However, it is only
recommended for higher voltage applications due to the large total collector-emitter
voltage drop. Another gate drive circuit includes an output transistor or a conventional
gate driver IC that supplies a constant base current to the switching element regardless of
the collector current and temperature. However, this gate drive circuit becomes very
inefficient in converters operating in discontinuous conduction mode, inverters, or in any
converter where the current flowing through the SiC BJT’s is not constant.
Several gate drivers that provide proportional base current are developed
to overcome this issue. One such gate driver describes several parallel resistors connected
to a voltage supply that generates discretized base current. The base current is then
adjusted by enabling the number of resistance branches connected to the base to give the
proportional base current. Another approach describes a synchronous buck converter used
as gate driver. The regulated output voltage is connected to the base of the BJT to control
the amount of base current. Still other methods use a constant voltage source where the
base resistance is varied to change the base current. However, all the above methods are
based on current measurements which can be a challenge when higher bandwidths are
required. Moreover, these methods have a high complexity, due to the current
measurement needing to be processed in a digital signal processor (DSP) or a field-
programmable gate array (FPGA) to determine the number of branches to be enabled or
to calculate the duty cycle of the switches that control the base voltage. Also, some of
these drivers use the averaged inductor current for the calculation of the base current,
which allows the adjustment of the base current with respect to the variations of the load
and not with respect to instantaneous variations of the collector current.
In addition, prior gate drivers do not consider the effect of temperature on
the BJT’s DC current gain, which decreases with higher temperatures. This forces the
driver to always operate the BJT assuming the worst DC current gain, as if the BJT was
always operating at the maximum expected temperature. Such approach translates into
unnecessary driver power consumption when the actual operating temperature is below
the maximum, or in other words, when the DC current gain is not at its minimum.
Therefore, there is a need for an advanced gate driver for silicon carbide
(SiC) bipolar junction transistors (BJTs) to provide a proportional base current with
minimal power consumption and a method for optimizing the base current of the SiC BJT
utilizing the gate driver circuit. Such a gate driver would adjust the base current to the
instantaneous collector current by estimating the collector-emitter voltage. Further, such
a needed gate driver would monitor the effect of temperature on the DC current gain. Such
a gate driver would provide a continuous supply of base current to maintain the BJT in
the ON state. Such a gate driver would have minimum power loss during the ON state and
minimum switching losses, which increases the efficiency of the driver. Further, such a
driver would eliminate the need for the high bandwidth current sensors and the digital
signal processors to process collector current of the BJT. The present embodiment
overcomes shortcomings in the field by accomplishing these critical objectives.
SUMMARY OF THE DISCLOSURE
To minimize the limitations found in the existing systems and methods,
and to minimize other limitations that will be apparent upon the reading of this
specification, the preferred embodiment of the present invention provides an advanced
gate driver circuit for silicon carbide (SiC) bipolar junction transistors (BJTs) and a
method for optimizing the base current of the SiC BJT utilizing the gate driver circuit.
The gate driver circuit comprises a sensor connected between a collector
terminal and an emitter terminal of the BJT, an amplifier, a regulator and a gate driver
connected to a base terminal of the BJT. The sensor is configured to sense and measure a
collector-emitter voltage V across the collector terminal and the emitter terminal during
the ON state of the BJT. The sensor comprises a first resistor and a second resistor
connected in series, a high voltage diode with an anode connected between the series
connected first and second resistors and the cathode connected to the collector terminal
of the BJT and a first capacitor connected parallel to the second resistor. The sensor can,
preferably, be a high voltage decoupling diode.. The sensor provides a sensor output
voltage V based on the measured collector-emitter voltage V The amplifier is
m CE.
connected to a sensor output terminal across the first capacitor and is configured to
amplify the sensor output voltage V . The amplifier comprises a non-inverting
operational amplifier controlled by means of a plurality of resistors, a voltage follower
connected to an output of the non-inverting operational amplifier through a first diode and
a third resistor connected across the voltage follower configured to provide the output of
the amplifier. The amplifier is selected to provide rail-to-rail operation, high bandwidth,
good noise immunity and with the ability to modify gain depending on the requirement of
the base current I based on collector-emitter voltage V . The amplifier is configured to
b CE
amplify the sensor output voltage V to provide an amplifier output voltage V The
m ref.
regulator is connected to an amplifier output terminal and is configured to regulate a
regulator output voltage V based on the amplifier output voltage V . The amplifier
cc ref
output voltage V is used as a voltage reference for the regulator, which behaves like a
buffer. The gate driver is connected to a regulator output terminal and is configured to
connect/disconnect the regulator output voltage V to the base terminal of the BJT. With
the regulator output voltage V , the gate signals are generated internally in accordance
with the amplifier output voltage V . The regulator regulates the voltage of the gate driver
to generate the instantaneous proportional base current I based on the collector-emitter
voltage V during the conducting state of the BJT and thereby minimizing the driver
losses.
The method for optimizing the base current of the SiC BJT utilizing the
gate driver circuit comprises the steps of: providing the gate driver circuit having a sensor,
an amplifier, a regulator and a gate driver. Then sensing and measuring a collector-emitter
voltage by the sensor based on a collector current during the conducting state of the BJT.
Then providing the measured sensor voltage to the amplifier of the gate driver circuit and
generating an amplifier output voltage and providing the amplifier output voltage to the
regulator and generating a regulated voltage based on the collector-emitter voltage of the
BJT. Then supplying the regulated voltage output of the regulator to the gate driver and
optimizing the base current of the BJT based on the regulated voltage output of the
regulator and the collector-emitter voltage of the BJT.
It is a first objective of the present invention to provide an advanced gate
driver circuit for silicon carbide (SiC) bipolar junction transistors (BJTs) that provides a
proportional base current with minimal power consumption.
A second objective of the present invention is to provide a gate driver that
adjusts the base current to the instantaneous collector current by estimating the collector
current by means of the collector-emitter voltage.
A third objective of the present invention is to provide a gate driver that
monitors the effect of temperature on the DC current gain.
A fourth objective of the present invention is to provide a gate driver that
provides a continuous supply of base current to maintain the BJT in the ON state.
Another objective of the present invention is to provide a gate driver with
minimum power losses during ON state and switching that increases the efficiency of the
driver.
Yet another objective of the present invention is to provide a driver that
eliminates the need for the high bandwidth current sensors and the digital signal
processors to process collector current of the BJT.
These and other advantages and features of the present invention are
described with specificity so as to make the present invention understandable to one of
ordinary skill in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
Elements in the figures have not necessarily been drawn to scale in order
to enhance their clarity and improve understanding of these various elements and
embodiments of the invention. Furthermore, elements that are known to be common and
well understood to those in the industry are not depicted in order to provide a clear view
of the various embodiments of the invention, thus the drawings are generalized in form in
the interest of clarity and conciseness.
illustrates a block diagram of a gate driver circuit of a silicon carbide
bipolar junction transistor (SiC BJT) in accordance with the preferred embodiment of the
present invention;
illustrates a circuit diagram of the gate driver circuit of the SiC BJT
in accordance with the preferred embodiment of the present invention;
illustrates a block diagram of the gate driver circuit of the SiC BJT
in accordance with one embodiment of the present invention;
illustrates a graph illustrating the waveforms generated at different
stages of the gate driver circuit of the SiC BJT in accordance with an exemplary
embodiment of the present invention;
illustrates graphs that show the reduction of the driver power
consumption with respect to the output power of the converter of the present gate driver
circuit and different existing gate drivers in accordance with the exemplary embodiment
of the present invention; and
illustrates a flowchart of a method for optimizing the base current
of the SiC BJT utilizing the gate driver circuit in accordance with the preferred
embodiment of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
In the following discussion that addresses a number of embodiments and
applications of the present invention, reference is made to the accompanying drawings
that form a part hereof, and in which is shown by way of illustration specific embodiments
in which the invention may be practiced. It is to be understood that other embodiments
may be utilized and changes may be made without departing from the scope of the present
invention.
Various inventive features are described below that can each be used
independently of one another or in combination with other features. However, any single
inventive feature may not address any of the problems discussed above or only address
one of the problems discussed above. Further, one or more of the problems discussed
above may not be fully addressed by any of the features described below.
As used herein, the singular forms "a", "an" and "the" include plural
referents unless the context clearly dictates otherwise. “And” as used herein is
interchangeably used with “or” unless expressly stated otherwise. As used herein, the term
‘about” means +/- 5% of the recited parameter. All embodiments of any aspect of the
invention can be used in combination, unless the context clearly dictates otherwise.
Unless the context clearly requires otherwise, throughout the description
and the claims, the words ‘comprise’, ‘comprising’, and the like are to be construed in an
inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense
of “including, but not limited to”. Words using the singular or plural number also include
the plural and singular number, respectively. Additionally, the words “herein,” “wherein”,
“whereas”, “above,” and “below” and words of similar import, when used in this
application, shall refer to this application as a whole and not to any particular portions of
the application.
The description of embodiments of the disclosure is not intended to be
exhaustive or to limit the disclosure to the precise form disclosed. While the specific
embodiments of, and examples for, the disclosure are described herein for illustrative
purposes, various equivalent modifications are possible within the scope of the disclosure,
as those skilled in the relevant art will recognize.
Referring to FIGS. 1-2, a block diagram and a circuit diagram of a gate
driver circuit 100 of a silicon carbide bipolar junction transistor (SiC BJT) 102 in
accordance with the preferred embodiment of the present invention are illustrated
respectively. SiC BJTs have very low specific on-resistance and offer high temperature
operation due to the lack of gate oxide. This makes them very suitable for power switches
and for applications with high power densities. A continuous supply of base current IB is
needed to maintain the SiC BJT in the ON state. The gate driver circuit 100 of the present
embodiment provides the continuous base current IB based on the collector-emitter
voltage VCE of the SiC BJT 102. The present invention provides a proportional base
current driver circuit 100 that adjusts the base current IB to the instantaneous collector
current IC by estimating the collector-emitter voltage VCE and at the same time
monitoring the effect of temperature on the DC current gain.
The collector-emitter voltage VCE drop across the BJT 102 during the ON
state is used to estimate the collector current IC, rather than measuring the current directly.
Hence, the collector-emitter voltage VCE measurement is used to determine the required
base current IB to drive the SiC BJT 102. As the operating temperature of the BJT 102
increases, the amount of the base current IB required for the same collector current
increases, because the DC current gain decreases with temperature. Moreover, the on-
resistance of SiC BJTs also increases with temperature, which for the same collector
current IC results in a higher collector-emitter voltage drop. This increase in the voltage
drop compensates for the decrease of the DC current gain, which offers the possibility of
accomplishing temperature-sensitivity without measuring the temperature.
The gate driver circuit 100 of the present embodiment comprises a sensor
110 connected across a collector terminal 104 and an emitter terminal 106 of the BJT 102,
an amplifier 122, a regulator 134 and a gate driver 144 connected to a base terminal 108
of the BJT 102. The sensor 110 is configured to sense and measure a collector-emitter
voltage VCE across the collector terminal 104 and the emitter terminal 106 during the ON
state of the BJT 102. The sensor 110 comprises a first resistor 112 and a second resistor
114 connected in series, a high voltage diode 116 with an anode 152 connected between
the series connected first and second resistors 112, 114 and the cathode 154 connected to
the collector terminal 104 of the BJT 102 and a first capacitor 118 connected parallel to
the second resistor 114. The sensor 110 can, preferably, be a high voltage decoupling
diode. In one embodiment, the sensor 110 is a Zener diode voltage clamp. The sensor 110
provides a sensor output voltage Vm based on the measured collector-emitter voltage
VCE. The sensor 110 detects changes in the temperature of the BJT via its on-state
resistance. The amplifier 122 is connected to a sensor output terminal 120 and is
configured to amplify the sensor output voltage Vm. The measured values of the sensor
output Vm indicates that with the increase in the collector current IC, the sensor output
Vm is also increased. Thus, the sensor output voltage Vm is proportional to the collector-
emitter voltage VCE which in turn is proportional to the collector current IC of the BJT
102 with an additional offset.
The high voltage decoupling diode 116 protects the circuitry comprising
the amplifier and the regulator, from high voltage during the OFF state of the BJT 102.
The sensor 110 of the present embodiment senses the collector current IC by measuring
the collector-emitter voltage VCE and thus eliminates the need for the high bandwidth
current sensors and the digital signal processors otherwise required to process collector
current IC.
In some other embodiments, sensors such as resistive voltage divider,
Zener limiting diode and low voltage MOSFET may be used.
The amplifier 122 comprises a non-inverting operational amplifier 124
controlled by means of a plurality of resistors 126, a voltage follower 128 connected to
the output of the non-inverting operational amplifier 124 by means of a first diode 130
and a third resistor 132 connected across the first diode 130 and the voltage follower 128.
The amplifier 122 is selected to provide high gain, good noise immunity and with the
ability to modify gain depending on the requirement of the base current IB based on
collector-emitter voltage VCE. The amplifier 122 amplifies the sensor output voltage Vm
to provide an amplifier output voltage Vref. The regulator 134 is connected to an amplifier
output terminal 140. The regulator 134 is configured to regulate a regulator output voltage
Vcc based on the amplifier output voltage Vref. The regulator 134, for example, is a non-
isolated synchronous buck converter. The amplifier output voltage Vref is used as a
voltage reference for the regulator 134. The gate driver 144 is connected to a regulator
output terminal 142 and is configured to connect/disconnect the regulator output voltage
Vcc to the base terminal of the BJT. With the regulator output voltage Vcc, the gate signals
are generated internally in accordance with the amplifier output voltage Vref. The
regulator 134 regulates the voltage of the gate driver 144 to generate the instantaneous
proportional base current IB based on the collector-emitter voltage VCE during the
conducting state of the BJT 102 and thereby minimizing the driver losses.
The power losses during the conduction state of the BJT 102 are
determined by the collector current IC and the On-resistance. The power losses generated
in the gate driver 144 can be calculated with base current IB, the base-emitter saturation
voltage (VBE(sat)), the internal base resistance (RBint), the external base resistance
(RBext) and the driver resistance (Rdriver).
A Pulse width modulated (PWM) signal 146 is used for controlling the gate
driver 144 output. The regulator 134 provides voltage supply to the gate driver 144 to
provide the continuous supply of base current IB to maintain the BJT 102 in ON state with
minimal conduction losses. The regulator 134, for example, can be an integrated circuit
(IC) with a synchronous buck converter inside (LTC3600). Thus, the gate driver circuit
100 of the present invention optimizes the base current IB based on the collector-emitter
voltage VCE by adjusting the voltage applied to the gate driver 144 by the regulator 134.
The output voltage of the regulator 134 is controlled by an inductor 136 and a capacitor
138 connected to the regulator output terminal 142. The gate driver 144 output voltage is
adjusted during the conducting state of the BJT 102. Thus, the operation of the present
invention includes the flow of collector current IC through the BJT that results in a voltage
drop across the collector-emitter terminals VCE, which is measured by the sensor 110.
The output of the sensor Vm is conditioned with the amplifier 122 that generates the
amplifier output Vref for the regulator 134. The regulator 134 buffers the amplifier output
Vref to output the voltage Vcc that causes the gate driver 144 to generate the required
base current IB to flow through the BJT 102 to keep it in ON state. Output voltage of the
regulator 134 is dependent on the temperature of the SiC BJT 102. The gate driver 144
optimizes the base current by monitoring the effect of temperature on the DC current gain
of the BJT.
illustrates a block diagram of the gate driver circuit 100 of the SiC
BJT 102 employing an isolated regulator 150. In this embodiment of the present invention,
an isolated regulator topology is utilized. The collector-emitter voltage VCE of the BJT
102 is measured by the sensor 110 and provided to the amplifier 122 which amplifies the
sensor output voltage as illustrated in In this embodiment, the amplified amplifier
output voltage is then applied to the isolated regulator 150. The isolated regulator 150 of
this embodiment is based on Flyback, Push-Pull, Half/fullBridge, etc. The isolated
regulator 150 is combined with an opto-coupler 148, digital isolator or pulse transformer,
for the PWM 146 signal. This embodiment illustrates the gate driver circuit with the
isolated regulator for a universal high/low side driver.
illustrates a graph illustrating the waveforms generated at different
stages of the gate driver circuit 100 of the SiC BJT 102 in accordance with an exemplary
embodiment of the present invention. The graphs summarize experimental results of the
gate driver circuit 100 of the present embodiment used to control the SiC BJT 102. In the
example illustrated in a Boost converter at room temperature for an output power
of 1.6kW is utilized. The pulse width modulated (PWM) control signal 146 for the SiC
BJT 102 is shown as waveform P. The waveform of the regulator output voltage Vcc and
the regulator output current IL through the inductor 136 is illustrated by Q and R
respectively. The continuous base current IB proportional to the regulator output voltage
Vcc is shown by the waveform S.
illustrates graphs depicting the driver power consumption with
respect to the output power of the converter of the present gate driver circuit 100 and an
existing gate driver in accordance with the exemplary embodiment of the present
invention. A Boost converter was utilized for this purpose. Experiments were carried out
on the existing gate driver and the gate driver circuit 100 of the present invention at room
temperature. Graphs were calibrated at different output power of the Boost converter.
Graphs A, B and C show the variation of the driver power consumption with respect to
the output power of the Boost converter of the existing gate driver for different values of
external base resistance. Graph D shows the variation of the driver power consumption
with respect to the output power of the Boost converter of the gate driver circuit 100 of
the present embodiment. The graphs reveal that the gate driver circuit 100 of the present
embodiment reduced the driver power consumption by a factor of 4 compared to the
existing gate driver.
The reduction of the driver power consumption offered by embodiments of
this invention is more noticeable in converters where the inductor current ripple is large
(e.g., converters operated in Discontinuous Conduction Mode or Resonant Converters)
and converters in applications where the operating temperature of the SiC BJT is expected
to fluctuate within a large temperature window.
Thus, the present invention 100 provides the proportional base current IB
based on the collector-emitter voltage VCE and eliminates high bandwidth current sensors
and micro-controllers. Embodiments of this invention also provide a standalone gate
driver circuit that replaces other switch and driver combinations using IGBTs or
MOSFETs, without any modifications at the converter level.
illustrates a flowchart of a method for optimizing the base current
of the SiC BJT utilizing the gate driver circuit in accordance with the preferred
embodiment of the present invention. The method comprises the steps of: providing the
gate driver circuit having a sensor, an amplifier, a regulator and a gate driver as indicated
in block 202. Sensing and measuring a collector-emitter voltage by the sensor based on a
collector current during the conducting state of the BJT as indicated in block 204. As
indicated in block 206, providing the measured sensor voltage to the amplifier of the gate
driver circuit and generating an amplifier output voltage and providing the amplifier
output voltage to the regulator and generating a regulated voltage based on the collector-
emitter voltage of the BJT as indicated in block 208. Applying the regulated voltage
output of the regulator to the gate driver as indicated in block 210 and optimizing the base
current of the BJT based on the regulated voltage output of the regulator and the collector-
emitter voltage of the BJT as indicated in block 212.
The present invention provides a novel design of the gate driver circuit 100
with minimal power consumption, adjusts the base current IB to the instantaneous
collector current IC by adjusting the driver voltage supply Vcc, based on the effect of
temperature on the DC current gain. The driver circuit 100 of the present embodiment can
be implemented in any power electronics converter topology including DC/DC
converters, inverters etc.
Embodiments of this invention also provide a standalone driver circuit that
can replace other switch plus driver combinations using IGBTs or MOSFETs, without
any modifications at the converter level.
The foregoing description of the preferred embodiment of the present
invention has been presented for the purpose of illustration and description. It is not
intended to be exhaustive or to limit the invention to the precise form disclosed. Many
modifications and variations are possible in light of the above teachings. It is intended that
the scope of the present invention not be limited by this detailed description, but by the
claims and the equivalents to the claims appended hereto.
Claims (25)
1. A gate driver circuit, comprising: a sensor connected between a collector terminal and an emitter terminal of a bipolar junction transistor (BJT), the sensor configured to sense and measure a collector-emitter voltage; an amplifier connected to a sensor output terminal and configured to amplify an output voltage from the sensor to produce an amplifier output voltage, wherein the amplifier comprises a non-inverting operational amplifier controlled by means of a plurality of resistors, a voltage follower connected to an output terminal of the non-inverting operational amplifier by means of a first diode and a third resistor connected across the voltage follower and the first diode configured to provide the output of the amplifier; a regulator connected to an amplifier output terminal and configured to regulate a regulator output voltage based on the amplifier output voltage; and a gate driver connected to a regulator output terminal and configured to connect/disconnect the regulator output voltage to a base terminal of the BJT; whereby the regulator regulates the voltage of the gate driver to generate an instantaneous proportional base current based on the collector-emitter voltage during the conducting state of the BJT thereby minimizing the driver losses.
2. The gate driver circuit of claim 1 wherein the sensor comprises a first resistor and a second resistor connected in series, a high voltage diode with an anode connected between the series connected first and second resistors and a cathode connected to the collector terminal of the BJT and a first capacitor connected parallel to the second resistor.
3. The gate driver circuit of claim 1 or claim 2 wherein the output voltage of the regulator is controlled by an inductor and a capacitor connected at a regulator output terminal.
4. The gate driver circuit of any one of claims 1 to 3 wherein the sensor is a high voltage decoupling diode.
5. The gate driver circuit of any one of claims 1 to 3 wherein the sensor is a Zener diode voltage clamp.
6. The gate driver circuit of any one of the preceding claims wherein the sensor is configured to measure the collector-emitter voltage V during the ON state of the BJT.
7. The gate driver circuit of claim 4 wherein the high voltage decoupling diode protects the circuitry comprising the amplifier and the regulator, from high voltage during the OFF state of the BJT.
8. The gate driver circuit of any one of the preceding claims wherein the sensor output voltage is proportional to the collector current of the BJT with an additional offset.
9. The gate driver circuit of any one of the preceding claims wherein the amplifier is selected to provide high gain, good noise immunity and with the ability to modify gain depending on the requirement of the base current based on collector-emitter voltage.
10. The gate driver circuit of any one of the preceding claims wherein the amplifier output is used as a voltage reference to the regulator.
11. The gate driver circuit of any one of the preceding claims wherein the regulator is a synchronous buck converter.
12. The gate driver circuit of any one of the preceding claims wherein the regulator provides voltage to the gate driver to provide the continuous supply of base current to maintain the BJT in ON state with minimal conduction losses.
13. The gate driver circuit of any one of the preceding claims wherein the gate driver optimizes the base current based on the collector-emitter voltage by adjusting the supply voltage of the gate driver thereby minimizing the power consumption.
14. The gate driver circuit of any one of the preceding claims wherein the gate driver has an output voltage, the output voltage adjusted during the conducting state of the BJT.
15. The gate driver circuit of any one of the preceding claims wherein the gate driver optimizes the base current by monitoring an effect of temperature on the DC current gain.
16. The gate driver circuit of any one of the preceding claims wherein the sensor eliminates the need for the high bandwidth current sensors and the digital signal processors to process collector current of the BJT.
17. The gate driver circuit of any one of the preceding claims wherein the regulator output voltage is dependent on the temperature of the BJT.
18. The gate driver circuit of any one of the preceding claims, wherein the BJT is a Silicon Carbide Bipolar Junction Transistor (SiC BJT).
19. The gate driver circuit of any one of the preceding claims having a gate driver output, wherein a pulse width modulated (PWM) signal is used for controlling the gate driver output.
20. The gate driver circuit of claim 19, further comprising an opto-coupler, digital isolator or pulse transformer for the PWM signal.
21. A method for optimizing the base current of a Silicon Carbide Bipolar Junction Transistor (SiC BJT) utilizing a gate driver circuit, the method comprising: a) providing the gate driver circuit having: a sensor; an amplifier comprising a non-inverting operational amplifier controlled by means of a plurality of resistors, a voltage follower connected to an output terminal of the non-inverting operational amplifier by means of a first diode and a third resistor connected across the voltage follower and the first diode configured to provide the output of the amplifier; a regulator; and a gate driver; b) sensing and measuring a collector-emitter voltage by the sensor based on a collector current during the conducting state of the SiC BJT; c) providing the measured sensor voltage to the amplifier of the gate driver circuit and generating an amplifier output voltage; d) providing the amplifier output voltage to the regulator and generating a regulated voltage based on the collector-emitter voltage of the SiC BJT; e) applying the regulated voltage output of the regulator to the gate driver; and f) optimizing the base current of the SiC BJT based on the regulated voltage output of the regulator and the collector-emitter voltage of the SiC BJT.
22. The method of claim 21 wherein the collector-emitter voltage is measured during the ON state of the SiC BJT.
23. The method of claim 21 or claim 22 wherein the gate driver optimizes the base current based on the collector-emitter voltage by adjusting the supply voltage of the gate driver thereby minimizing the power consumption.
24. The method of any one of claims 21 to 23 wherein the regulator regulates the voltage of the gate driver to generate the instantaneous proportional base current based on the collector-emitter voltage during the conducting state of the SiC BJT thereby minimizing the driver losses.
25. The method of any one of claims 21 to 24 wherein the sensor detects changes in temperature of the SiC BJT via its on-state resistance.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US201762520645P | 2017-06-16 | 2017-06-16 | |
| US62/520,645 | 2017-06-16 | ||
| US15/990,881 US10715135B2 (en) | 2017-06-16 | 2018-05-29 | Advanced gate drivers for silicon carbide bipolar junction transistors |
| US15/990,881 | 2018-05-29 | ||
| PCT/US2018/036817 WO2018231668A1 (en) | 2017-06-16 | 2018-06-11 | Advanced gate drivers for silicon carbide bipolar junction transistors |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| NZ759815A NZ759815A (en) | 2021-03-26 |
| NZ759815B2 true NZ759815B2 (en) | 2021-06-29 |
Family
ID=
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11190179B2 (en) | Advanced gate drivers for silicon carbide bipolar junction transistors | |
| US10644581B2 (en) | DC-DC power conversion circuitry with efficiency optimization using temperature sensing | |
| US7643322B1 (en) | Dual loop constant on time regulator | |
| US8525423B2 (en) | Circuitry for driving light emitting diodes and associated methods | |
| US9621020B2 (en) | Control circuits and methods for controlling switching devices | |
| US11056965B2 (en) | Gate driver and power converter | |
| JP2001078439A (en) | Switching power supply device | |
| US11971433B2 (en) | Current measuring device for switched-mode power converters and regulation circuit for application of the current measuring device | |
| US8207779B2 (en) | Control circuits and methods for controlling switching devices | |
| JP2018005323A (en) | Voltage current conversion circuit and load drive circuit | |
| US20090284303A1 (en) | Control circuits and methods for controlling switching devices | |
| CN112332648B (en) | Device and method for actively balancing thermal performance of parallel power devices | |
| JP2013250222A (en) | High side current detection circuit | |
| NZ759815B2 (en) | Advanced gate drivers for silicon carbide bipolar junction transistors | |
| US20070014063A1 (en) | Single pin multi-function signal detection method and structure therefor | |
| US12388365B2 (en) | Auxiliary circuit of power converter and driving circuit | |
| US20150040584A1 (en) | Driver for thermo-electric cooler | |
| HK40011193A (en) | Advanced gate drivers for silicon carbide bipolar junction transistors | |
| HK40011193B (en) | Advanced gate drivers for silicon carbide bipolar junction transistors | |
| CN117277803A (en) | Current sensing system and DC-DC converter including the same | |
| US20250246989A1 (en) | Gate drive circuit and method for switching a semiconductor switch | |
| JP2003315378A (en) | Current detector | |
| Pozo et al. | Improved proportional base driver for SiC BJTs | |
| CN120033967A (en) | Switching converter and its controller and integrated control circuit | |
| JP2016134667A (en) | Current output device and current output method |