JP2767239B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]   The present invention relates to a voltage regulator integrated circuit (hereinafter referred to as a voltage regulator).
Internal resistance of semiconductor devices such as IC for regulator)
Related to the structure. [Conventional technology]   Conventional C / MS voltage regulator ICs are
In the case of an output voltage regulator, a circuit structure as shown in FIG.
It has become successful. Output control MS transistor 6 and negative
Connected between the power supply terminal 3 (hereinafter referred to as GND terminal)
Built-in resistors 7 and 8 in the voltage regulator IC,
As shown in FIG.^-P on the substrate^-Forming and using area
Was. [Problems to be solved by the invention]   However, in the conventional structure shown in FIG.
Child 1 (hereinafter V_INChanges in the voltage applied to the
Following, P^-Region and N^-Reverse bias applied between substrates
The voltage changes. Reduces current consumption of voltage regulator IC
P^-Lower the density of the area and increase the sheet resistance
Then V_INP due to change in input voltage applied to terminal 1^-
The change in the depletion layer region on the region side increases,
The resistance value and the resistance ratio change. Therefore, the output shown in FIG.
Output voltage at detection point A of output voltage change obtained by dividing the voltage by resistance
The resistance division value of fluctuates with the change of the input voltage,
The ratio of the change in output voltage to the change in input voltage (hereinafter,
Input stability).
Was.   Therefore, the present invention solves such a problem.
The purpose is to use the voltage regulator of the MS structure.
Built-in ICs for changes in input voltage
Resistance and resistance due to changes in the depletion layer
It is proposed to eliminate fluctuations in drag ratio and improve input stability.
To offer. [Means for solving the problem]   The semiconductor device of the present invention has a first terminal having a first potential.
Between a terminal and a second terminal having a second potential that is a fixed potential.
A first conductivity type diffusion resistor connected between the first and second diffusion resistors,
A semiconductor device having an input terminal disposed adjacent to the
And the expansion due to a change in the potential of the input terminal.
In order to prevent a change in the depletion layer of the diffusion resistance, the diffusion resistance is
A second conductivity type well supplied with a potential from the second terminal;
And the input terminal is located outside the well
Being provided on a semiconductor substrate of the first conductivity type.
I do. (Operation)   According to the above structure of the present invention, the resistor built in the IC.
One end of the resistance area forms the output terminal, and the other end forms a resistor
To the same potential as the substrate or well region
The resistance area built into the IC and the resistance area
Reverse bias voltage between the substrate or well region
Is hardly affected by fluctuations in the input voltage.
Due to reverse bias voltage change in the resistance region
Fluctuation of resistance value and resistance division ratio due to change of scarce region
And the input stability can be improved. 〔Example〕   Hereinafter, the present invention will be described in detail based on examples.
You. FIG. 1 is a view showing a device inside an IC according to a specific embodiment of the present invention.
1 shows a sectional view of a physical structure. Fig. 2 shows the positive output voltage
Fig. 2 shows a circuit diagram of an IC for a urator. 1 is V_INTerminal 2,
Output voltage terminal (hereinafter, V_UT3) GND
Terminals 4 and 4 are constant reference bases independent of power supply voltage.
A reference voltage generating circuit for generating a reference voltage, 5
Voltage at detection point A of output voltage change obtained by dividing output voltage by resistance
, And a voltage comparator 6 receives the output of the voltage comparator 5
Input to gate electrode, source electrode to V_INConnect to terminal 1
Rain electrode is V_UTFor output control connected to terminal 2
MS transistors, 7, 8 are V_UTTerminal 2 and GND terminal 3
Is a resistor connected between the two.   Next, the operation of the voltage regulator in the circuit diagram of FIG.
Will be described. V_INInput voltage is applied between terminal 1 and GND terminal 3.
And V_UTA load is connected between terminal 2 and GND terminal 3.
Load current flows. In this case, for example, the load current
Is ΔI The output voltage decreases. This output
Voltage drop to V_UTConnected between terminal 2 and GND terminal 3
Output voltage change by dividing the output voltage by resistors 7 and 8
At the detection point A and compared with the reference voltage by the comparator 5.
Amplify the deviation and V_INTerminal 1 and V_UTConnect between terminals 2
The output voltage is controlled by the connected output control MS transistor 6.
If the pressure is controlled in a rising direction, the fluctuation of the output voltage will be suppressed.
It is. That is, the fluctuation of the output voltage is
Is detected by the voltage at the detection point A of the output voltage change obtained by dividing
Output and feed back to the output control MS transistor 6.
A stable power supply can be obtained. Resistance 7,8
The resistance of R₇, R₈And the output voltage is V_UT, Reference voltage
V_REFThen, the output electric phase V_UTIs represented by the following equation.   Therefore, the output voltage V_UTIs R₇And R₈Resistance ratio and V_REFTo
Determined by   Now, the input voltage V_INIs V₁To V_Two(V₁<V_TwoUntil)
When it changes, the conventional N as shown in FIG.^-Formed on the substrate
P^-In the structure of the resistance using the region, P^-One side of the area
The end is connected to GND terminal 3 and N^-Substrate is V_INTo terminal 1
Connected, P^-Region and N^-Reverse buy between substrates
Ass voltage V_RIs the input voltage V_1NDirectly affected by fluctuations in^-
Resistance value and resistance ratio of resistors 7 and 8 according to the change of the depletion layer in the region
Changes. Output voltage V_UTIs the above equation (1)
R as shown in₇And R₈Ratio (R₇/ R₈Changes by
You. Input voltage V_1NThe change of P^-Region and N^-Span between substrates
Reverse bias voltage V_RR₇And R₈Ratio R₇/ R₈Is
Not constant, V_RR increases as₇Relative to
R₈Shows a large resistance value and shows characteristics as shown in FIG.
You. Therefore, the input voltage V_1NWith the change of R₇/ R₈Starts to change
Force voltage V_UTCauses the input stability to change
Cause.   In contrast, the P of the present invention shown in FIG.^-In the well area
N formed on^-In the structure of the resistor using the area, N^-Area
One end is V_UTConnected to terminal 2 and the other end is GN
Connected to D terminal 3 and N^-P where the area is formed^-C
Input voltage V_1NIs V₁To V
_TwoChanges to N^-Region and N^-P where the area is formed^-Ue
Reverse bias voltage V applied between_RHahoton
Since it does not change, R₇, R₈And R₇/ R₈Does not change and the output voltage
V_UTCan be suppressed.   The above embodiment is for a positive output voltage regulator.
However, even with a negative output voltage regulator, the structure of the present invention can be implemented.
Alms are possible. 〔The invention's effect〕   As described above, according to the present invention, the potential is
By providing a well supplied with
By preventing the change of the depletion layer of the diffusion resistance due to the change of the potential,
Device having a diffused resistor having a stable resistance value
That have the remarkable effect of being able to provide
It is.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a specific structure inside an IC according to a specific embodiment of the present invention. Fig. 2 is for positive output voltage regulator
FIG. FIG. 3 is a cross-sectional view of the structure of a resistor incorporated in a conventional voltage regulator IC. Figure 4 is a reverse bias voltage V _R to-resistance ratio R ₇ / R ₈ characteristic diagram which is applied between the substrate or well region is formed between the resistor region resistance region. 1 _V1N terminal 2 _VUT terminal 3 GND terminal 4 Reference voltage generating circuit 5 Voltage comparator 6 Output control MS transistors 7 and 8 Resistance

Claims (1)

(57) [Claims] A first conductivity type diffusion resistor connected between a first terminal having a first potential and a second terminal having a second potential which is a fixed potential; and a diffusion resistor arranged adjacent to the diffusion resistor. A semiconductor device having an input terminal, wherein the diffusion resistor is supplied with a potential from the second terminal so as to prevent a change in a depletion layer of the diffusion resistor due to a change in the potential of the input terminal. A semiconductor device provided in a well of a second conductivity type, wherein the input terminal is provided on a semiconductor substrate of a first conductivity type located outside the well.