TW200416657A - Lower-power-comsumption voltage generator - Google Patents

Abstract

A low-power-consumption LCD voltage generator controls and provides stable voltages to a device. The voltage generator circuit contains an initial power regulator and a charge pump, voltage source to provide a voltage flowing through generators in capacitive voltage divider. The capacitive voltage divider of the power supply regulator provides voltage in controlled voltage.

Description

200416657 V. Description of the invention (1) Background of the invention: The methods used by the LCD display voltage generator (Lcd vOltage generator) are: 1 · resistance partial voltage method; 2 · voltage doubler method, these two types Although the method can be used for various voltages required by the liquid crystal display (L c D pane 1), there are still some disadvantages: The lack of the resistance voltage division method (as shown in Figure 丨) ·· 1 When used for low power voltage, LCD vol tage Because the voltage provided by the generator is limited by the low power supply voltage, the V5 and V5 voltages are limited, which affects the display effect of the LCD panel. 2. In terms of power consumption, generally this method consumes about 151 ^ ~ 2OuA 'To reduce the power consumption, you need to increase the resistance to achieve this purpose', but the current is reduced, but the overall The chip size (ch ip si ze) becomes larger at design time. The lack of voltage multiplication method (see Figure 2): When using this method, 'when the power supply voltage is reduced, it will cause the ¥ 5 voltage to be limited and the desired multiple cannot be obtained. As a result, V5 ~ V4 and V4 ~ V3 The voltage will be unbalanced, and as a result, a dc bias will be generated to cause damage to the LCD panel. Purpose and summary of the invention (as shown in FIG. 3): The power supply voltage (VDD0) used in the present invention = 2. 4 to 3. 6 V.

200416657 V. Description of the invention (2) In order to avoid the limitation of the VI ~ V5 voltage caused by the change of the power supply voltage (VDD0), the reference voltage source (Vref) comes from a group of original voltage source regulators (p0Wer supply regulator), which can provide a The reference voltage source and the stable power used in the internal circuit generate vi & VH (charge pump vol tage) by the stable voltage provided by the power supply regulator (regulator for short). In addition, V1 and V5 are divided into two groups: V1 & V2 and V3 to V5. VH (charge pump voltage):

The voltage charging pump (VH) uses two external 1 · 1 capacitors to charge (CUPO &CUP1; CUP2 & CUP3) to charge VH to 7.5V, and we use the capacitor voltage division mechanism to detect VH to The reference voltage provided by the regulator is the reference point of the detect VH. When the detected VH voltage is lower than 7.5V, the pump circuit immediately pumps the VH voltage to 7.5V, so that the VH voltage can maintain a certain high voltage. It is within range and will not breakdwn. This voltage is used to provide the working power of the V5 Buffer. Because the vjj voltage is a high voltage level, it can provide a larger voltage range to the V5 Buffer, so that the V5 voltage will not occur higher than the VH voltage, and the V5 voltage will be affected. Limits, which in turn affects the performance and use of other circuit functions. V1 (as shown in Figure 4): VI is constant voltage, which is the reference for generating V2 ~ V5 voltage. VI is also the voltage generated by using the stable voltage provided by regUiator as a reference. In addition, there are 4 switching pin control signals to control V1.

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Page 5 200416657 V. Description of the invention (3) The VI voltage is adjusted by the control signal. Therefore, ^ is "" with adjustable voltage output, which can be used to determine the brightness of the LCD display. In addition, a P-type amplifier (P-type 0P) is used with single-sided output, and the buffer (Buf fer) power is the system power supply voltage. [Capacitive voltage division] The method of capacitive voltage division is mainly aimed at: The consideration of "electricity" and "overall size". The traditional method uses a resistor divider method. Using this method often cannot achieve a good balance between "power consumption" and "overall chip size." Consider the "power consumption". In order to achieve power saving, the resistance must be very large. As a result, the "power consumption" is reduced, but the "Ch ips 丨 ze" section becomes larger, so using this method has this Disadvantages. Therefore, using this method, the overall power consumption is about 15UA ~ 20uA. ', And the method of using capacitor voltage division is to use the method of capacitor charge and discharge to achieve or 4 will tolerate a large area like a capacitor. Compared with the method of resistance voltage division, its overall size still saves a lot; and the "power consumption" also reduces power consumption by about 80% compared to the method of resistance voltage division (using capacitor voltage division ^ ^ power consumption) About 5uA), so use the method of capacitive voltage division Good results can be obtained V 2 (FIG. 5):. V2 is twice the voltage V1, the charging voltage by capacitive charge to twice η

Page 6 200416657 V. Description of the invention (4) ’The N-type 0P buffer is used to output the buffer. The working power of the buffer is V5. V 5 (as shown in Figure 6): V5 is based on VI and has 3 switching pin control signals to control V5. This control signal can be used to adjust the feedback capacitor ratio and adjust the V5 voltage. 'Can be used to determine the brightness of the LCD display. In addition, the 'Buffer uses N-type 0P and unilateral output, and the working power of the buffer is Charge pump voltage (VH). V5 = VI x N bit; (N 2 3 · 5 ~ 7 · 0) We can find from the above that adjusting contrast (contrast) or bias (Bias) can affect the brightness of LCD di splay. In addition, it can be found from the relationship between b and VI that no matter how you adjust contrast or Bias, it will affect the voltage value of V5, but if you adjust Bias alone, it will only affect V5 and will not affect VI. V4 (as shown in Figure 7): The voltage of V4 is (V5-VI), which is achieved by capacitor charging.

200416657 V. Description of the invention (5) V3 (as shown in Figure 8): The voltage of V3 is (V4-VI), which is achieved by capacitor charging. Then output it as N-type OP Buffer, whose working power is V5. Therefore, the correlation of each voltage is:

VI

V2 = 2V1 V 3 — V 4 — V1 V4 = V5 -VI V5 = VI XN bit; (N = 3. 5 to 7. 0) As can be clearly seen from the above relationship, the present invention divides Vb V5 into two Group, VI & V2 — group, V3 ~ V5 — group, this approach will solve some of the shortcomings. There are some disadvantages of the traditional resistance voltage division method: 1. When the power supply voltage decreases, the VI ~ V5 voltage will decrease, and the constant voltage will also decrease. 'As a result, the brightness of the LCD will drop rapidly, affecting the LCD disp1 ay. 2. The MV5 voltage change ’is prone to cause unbalance between vg, γ4 and γ3, so that the DC bias still exists in the LCD pane. In this way, it is easy to cause panel damage and dim brightness. The mechanism of the present invention divides VI to V5 into: V1 & V2-group, V3 ~ V5-group.

200416657

V. Description of the invention (6) ί. Because the VI voltage is provided by reguiat〇r, it will not change drastically due to the white and change of the power supply voltage, so it can have a very stable ⑶ "" With the voltage, j this come 'even if Changes in the power supply voltage will not cause the LCD brightness to fall sharply ^. When V5 changes, it has less effect on LCD brightness. 2. From the above relationship, we can understand that there is a fixed range between the voltages of V5, V4, and V3. Even if V5 changes, V4 & V3 also changes along with it, maintaining a fixed range ran§e. The presence of DC bias will not cause damage to the panel.

200416657 Brief description of the diagram The first diagram of the prior art resistor voltage division method The second diagram of the prior art voltage doubler mode The third diagram of the voltage generator of the present invention

The fourth figure is the first voltage source (VI) of the voltage generator of the present invention. The fifth figure is the second voltage source (V2) of the voltage generator of the present invention. The sixth figure is the fifth voltage source (V5) of the voltage generator of the present invention. Figure 4th voltage source (V4) of the voltage generator of the present invention Figure 8th voltage source (V3) of the voltage generator of the present invention

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Claims (1)

200416657 6. Scope of patent application Patent scope: 1. A low power consumption and stable liquid crystal display (LCD) voltage generator device 'uses a reference voltage source (Vref) and a system voltage source (VDD0), including : A reference voltage source generator, called a first voltage source generator (V i Generator); and a voltage charging pump (VH) circuit to generate VH voltage, which regulates a stable voltage output; and multiple sets of voltage generator devices, according to The system needs to generate the required voltage. 2 · The device according to item 1 of the scope of patent application, wherein the reference voltage source generator (VI Generator) is a reference voltage source (Vref) via a P-type amplifier (P-type 0P), and its buffer power source is the system For the voltage source (VDD0), the switching voltage is used to control the capacitor voltage division, and the feedback is adjusted to obtain the required voltage, which is called the reference voltage source and also called the first voltage source (V1). 3. The device according to item 1 of the scope of patent application, wherein the voltage charging pump (VH) voltage VH uses the external capacitor of the voltage charging pump circuit to charge the reference voltage source (Vref) to a set high level voltage VH; The capacitor voltage is used for detection, and it can be charged to a high level voltage in time to make the electric ink generator stable and normal operation. 200416657 4. The device according to item 1 of the scope of patent application, wherein the multiple sets of voltage generator devices are as follows: The fifth voltage source generator (V5 Generator) is based on the reference voltage (vi) and passed through an N-type amplifier (N-type 0P ), Using the voltage charging pump voltage (VH) as the buffer (Buf fer) voltage, applying a switching pin to adjust the feedback capacitor's voltage division ratio, and adjusting the output fifth voltage (V5). The fourth voltage source generator (V4 Generator) is obtained by subtracting the fifth voltage from the reference voltage (V 5 -V1), which is achieved by using a capacitor charging method. The voltage is fed back through an N-type amplifier (N-type 0P). Is V4, and the fifth voltage (V5) is used as a buffer voltage to generate a fourth voltage (V4). The third voltage source generator (V3 Generator) is obtained by subtracting the fourth voltage from the reference voltage (V4-VI) and using a capacitor charging method. After the N-type amplifier (N-type 0P), the feedback voltage is V3 uses the fifth voltage (V5) as a buffer voltage to generate a third voltage (V3). With this architecture, even if the power supply voltage drops, causing the V 5 voltage to drop, it can still maintain a fixed ratio change between V 5 and V 4 & V 3. The second voltage source generator (V2 Generator) uses the capacitor charging method to charge the reference voltage (VI) to twice the reference voltage 2 (V1), passes the N-type 0P, and feeds back the voltage. Is V2, and the fifth voltage (V5) is used as a buffer voltage to generate a second voltage (V2). 200416657 VI. Scope of patent application The framework of the present invention divides VI ~ V5 into two groups: V1 & V2—group, V3 ~ V5—group, each voltage and voltage have a fixed ratio, even if the power supply voltage drops, V1 ~ V 5 The voltage ratio is still maintained, so that the LCD pane 1 will not have a DC bias (DC Bais) component, which will not cause damage and affect the LCD panel. 5. According to the device in the scope of the patent application, the low power consumption voltage generator uses a capacitor voltage division method to achieve the relationship between the reference voltage source and the multiple sets of voltage sources, and uses this method to achieve power saving. And the device that saves the area of crystal (IC). Page 13