A large-current screen driving circuit

Abstract

The utility model discloses a screen drive circuit of large current, including boost circuit, voltage doubler circuit and two voltage stabilizing circuit, input voltage first to boost voltage, then send into voltage doubler circuit and carry out voltage doubling, then output after voltage stabilizing circuit voltage stabilizing, two voltage stabilizing circuits are first voltage stabilizing circuit and second voltage stabilizing circuit respectively, realized multichannel voltage output under low cost, realize output voltage stabilization through increasing voltage reference chip and MOS pipe, and output current can reach 10mA.

Description

Technical Field

[0001] This utility model relates to the field of intelligent vehicles, specifically to a high-current screen driving circuit. Background Technology

[0002] With the increasing prevalence of smart cars, the number of displays on vehicles is also growing. Automotive TFT (Thin Film Transistor) displays typically require a gate capacitor drive voltage VGH (the voltage to turn on the TFT), a VGL (the voltage to turn off the TFT), and an analog voltage (AVDD) for power supply. The display's power supply involves multiple voltage paths and requires stability. Currently, screen power supply mainly uses a boost converter plus a voltage doubler circuit. While the voltage doubler circuit is low-cost and can generate multiple outputs, its driving capability is poor. In some cases where the screen requires a large current, it can pull down the supply voltage, causing the screen to fail to light up or display a distorted image. Utility Model Content

[0003] To address the problems existing in the prior art, this utility model provides a high-current screen driving circuit that achieves multi-channel voltage output at low cost. By adding a voltage reference chip and a MOSFET, the output voltage is stabilized, and the output current can reach 10mA.

[0004] The technical solution of this utility model is: a high-current screen driving circuit, including a Boost boost circuit, a voltage multiplier circuit and two voltage regulator circuits; the input voltage is first boosted by the Boost boost circuit, then sent to the voltage multiplier circuit for voltage multiplication, and then output after being regulated by the voltage regulator circuit;

[0005] The two voltage regulator circuits are a first voltage regulator circuit and a second voltage regulator circuit, respectively.

[0006] The first voltage regulator circuit includes a resistor R3, a voltage reference chip D3, a transistor Q1, voltage divider resistors R4 and R5, and a capacitor C5. One end of the resistor R3 is connected to the output terminal of the positive voltage doubler circuit of the voltage doubler circuit, which is also connected to the collector of the transistor Q1. The other end of the resistor R3 is connected to pin 3 of the voltage reference chip D3, which is also connected to the base of the transistor Q1. Pin 2 of the voltage reference chip D3 is grounded, and pin 1 of the voltage reference chip D3 is connected to the series voltage divider point of the voltage divider resistors R4 and R5. The other end of the voltage divider resistor R4 is connected to the emitter of the transistor Q1, which is also connected to one end of the capacitor C5 to serve as the voltage output terminal of the first voltage regulator circuit. The other end of the capacitor C5 is grounded. The other end of the voltage divider resistor R5 is grounded.

[0007] The second voltage regulator circuit includes a resistor R6, a voltage reference chip D5, a transistor Q2, voltage divider resistors R7 and R8, and a capacitor C8. One end of the resistor R6 is connected to the output terminal of the negative voltage doubler circuit of the voltage doubler circuit, which is also connected to the collector of the transistor Q2. The other end of the resistor R6 is connected to pin 2 of the voltage reference chip D5, which is also connected to the base of the transistor Q2. Pin 3 of the voltage reference chip D5 is grounded, and pin 1 of the voltage reference chip D5 is connected to the series voltage divider point of the voltage divider resistors R7 and R8. The other end of the voltage divider resistor R7 is connected to the emitter of the transistor Q2, which is also connected to one end of the capacitor C8 to serve as the voltage output terminal of the second voltage regulator circuit. The other end of the capacitor C8 is grounded. The other end of the voltage divider resistor R8 is grounded.

[0008] Furthermore, the Boost circuit includes capacitor C1, inductor L1, diode D1, Boost power chip RTQ9297, voltage divider resistor R1, voltage divider resistor R2 and capacitor C2.

[0009] The voltage input terminal of the Boost circuit is divided into three paths: one path is connected to one end of capacitor C1, one path is connected to pin 8 of the Boost power chip RTQ9297, and one path is connected to one end of inductor L1; the other end of capacitor C1 is grounded.

[0010] The other end of the inductor L1 is divided into two paths: one path is connected to the LX pin of the Boost power chip RTQ9297, and the other path is connected to the positive terminal of the diode D1. The negative terminal of the diode D1 is connected to one end of the capacitor C2, and the other end of the capacitor C2 is grounded. The positive and negative terminals of the diode D1 serve as the output terminals of the Boost boost circuit.

[0011] The voltage divider resistors R1 and R2 are connected in series to form a series voltage divider circuit; the series voltage divider point of the series voltage divider circuit is connected to pin 2 of the Boost power chip RTQ9297, the other end of the voltage divider resistor R1 is connected to the negative terminal of the diode D1, and the other end of the voltage divider resistor R2 is grounded.

[0012] Furthermore, the voltage multiplier circuit includes capacitor C3, capacitor C6, dual diodes D2 and D4, filter capacitor C4, and filter capacitor C7;

[0013] One end of capacitor C3 is connected to the positive terminal of diode D1 in the Boost circuit, and the other end of capacitor C3 is connected to pin 3 of dual diode D2. Pin 1 of dual diode D2 is connected to the negative terminal of diode D1 in the Boost circuit. Pin 2 of dual diode D2 is connected to one end of filter capacitor C4, and the other end of filter capacitor C4 is grounded.

[0014] One end of capacitor C6 is connected to the positive terminal of diode D1 in the Boost circuit, and the other end of capacitor C6 is connected to pin 3 of dual diode D4. Pin 2 of dual diode D4 is grounded, pin 1 of dual diode D4 is connected to one end of filter capacitor C7, and the other end of filter capacitor C7 is grounded.

[0015] The beneficial effects of this invention are: it provides a high-current screen driving circuit that achieves multi-channel voltage output at low cost; output voltage stability is achieved by adding a voltage reference chip and a MOSFET; and the output current can reach 10mA. It supports adjustment of the output voltage value and the number of voltage channels, facilitating its application in various screen driving circuits. Attached Figure Description

[0016] Figure 1 This is a system structure diagram of a high-current screen driving circuit. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings.

[0018] As attached Figure 1 As shown, this circuit mainly consists of three parts: a boost converter, a voltage multiplier, and a voltage regulator. The input voltage is first boosted by the boost converter, then doubled by the voltage multiplier, and finally regulated by the voltage regulator before being output.

[0019] Boost converter circuit: The input voltage is filtered by C1 (47uF) and then fed into inductor L1 (4.7uH). The output of inductor L1 is connected to the LX pin (pins 6 and 7) of the Boost power chip (RTQ9297), and also to the positive terminal of diode D1 (RB160VAM-40TR). The negative output of diode D1 is connected to capacitor C2 (4.7uF) to filter and output +8V voltage. Resistors R1 (54.5K) and R2 (10K) form a series voltage divider circuit to divide the +8V voltage output by C2 and then connect it to the FB pin (pin 2) of the power chip (RTQ9297).

[0020] Voltage multiplier circuit: One end of capacitor C3 (1uF) is connected to the anode of diode D1 in the Boost converter circuit, and the other end is connected to pin 3 of dual diode D2 (BAT54SLT1G). Pin 1 of dual diode D2 is connected to the +8V output voltage of the Boost converter circuit, and pin 2 of dual diode D2 is connected to filter capacitor C4 (1uF). Since the reference voltage of D2 is +8V and D2 has a forward voltage drop, the output voltage across C4 is approximately 15.2V. One end of capacitor C6 (1uF) is connected to the anode of diode D1 in the Boost converter circuit, and the other end is connected to pin 3 of dual diode D4 (BAT54SLT1G). Pin 2 of dual diode D4 is connected to GND, and pin 1 of dual diode D4 is connected to filter capacitor C7 (1uF). Since the reference voltage of D4 is 0V and D4 has a forward voltage drop, the output voltage across C7 is approximately -7.3V.

[0021] Voltage Regulator Circuit: The 15.2V output voltage from capacitor C4 is fed into pin 3 of the precision voltage reference chip D3 (TL431AIPK) via resistor R3 (2K). Pin 2 of voltage reference chip D3 is grounded. Pin 1 of voltage reference chip D3 is connected to the series voltage divider point of voltage divider resistors R4 (87K) and R5 (10K). The other end of resistor R4 is connected to the emitter (pin 2) of transistor Q1 (MMBT3904), and the other end of resistor R5 is grounded. The 15.2V output voltage from C4 is simultaneously connected to the collector (pin 3) of transistor Q1. The base (pin 1) of transistor Q1 is connected to pin 3 of voltage reference chip D3. Through voltage reference chip D3, transistor Q1 operates in the amplification region. The emitter (pin 2) of transistor Q1 outputs a voltage of +12V, which is fed into capacitor C5 (1uF) for filtering and voltage regulation before output. Transistor Q1 (MMBT3904) is used to increase the drive current to 10mA.

[0022] The -7.3V output voltage from capacitor C7 is fed through resistor R6 (2K) to pin 2 of the precision voltage reference chip D5 (TL431AIPK). Pin 3 of voltage reference chip D5 is grounded. Pin 1 of voltage reference chip D5 is connected to the series voltage divider point of voltage divider resistors R7 (10K) and R8 (85K). The other end of resistor R7 is connected to the emitter (pin 2) of transistor Q2 (MMBT3906), and the other end of resistor R8 is grounded. The -7.3V output voltage from C7 is simultaneously connected to the collector (pin 3) of transistor Q2. The base (pin 1) of transistor Q2 is connected to pin 2 of voltage reference chip D5. Through voltage reference chip D5, transistor Q2 operates in the amplification region, and the emitter (pin 2) of transistor Q2 outputs a -6V voltage, which is fed into capacitor C8 (1uF) for filtering and voltage regulation before being output. Transistor Q2 (MMBT3906) is used to increase the drive current to 10mA.

[0023] This invention provides a high-current screen driver circuit that achieves multi-channel voltage output at low cost. Output voltage stability is achieved by adding a voltage reference chip and MOSFETs, and the output current can reach 10mA. It supports adjustment of the output voltage value and the number of voltage channels, facilitating its application in various screen driver circuits.

[0024] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A high-current screen driving circuit, characterized in that: It includes a boost circuit, a voltage multiplier circuit, and two voltage regulator circuits; the input voltage is first boosted by the boost circuit, then doubled by the voltage multiplier circuit, and finally regulated by the voltage regulator circuit before being output. The two voltage regulator circuits are a first voltage regulator circuit and a second voltage regulator circuit, respectively. The first voltage regulator circuit includes a resistor R3, a voltage reference chip D3, a transistor Q1, voltage divider resistors R4 and R5, and a capacitor C5. One end of the resistor R3 is connected to the output terminal of the positive voltage doubler circuit of the voltage doubler circuit, which is also connected to the collector of the transistor Q1. The other end of the resistor R3 is connected to pin 3 of the voltage reference chip D3, which is also connected to the base of the transistor Q1. Pin 2 of the voltage reference chip D3 is grounded, and pin 1 of the voltage reference chip D3 is connected to the series voltage divider point of the voltage divider resistors R4 and R5. The other end of the voltage divider resistor R4 is connected to the emitter of the transistor Q1, which is also connected to one end of the capacitor C5 to serve as the voltage output terminal of the first voltage regulator circuit. The other end of the capacitor C5 is grounded. The other end of the voltage divider resistor R5 is grounded. The second voltage regulator circuit includes a resistor R6, a voltage reference chip D5, a transistor Q2, voltage divider resistors R7 and R8, and a capacitor C8. One end of the resistor R6 is connected to the output terminal of the negative voltage doubler circuit of the voltage doubler circuit, which is also connected to the collector of the transistor Q2. The other end of the resistor R6 is connected to pin 2 of the voltage reference chip D5, which is also connected to the base of the transistor Q2. Pin 3 of the voltage reference chip D5 is grounded, and pin 1 of the voltage reference chip D5 is connected to the series voltage divider point of the voltage divider resistors R7 and R8. The other end of the voltage divider resistor R7 is connected to the emitter of the transistor Q2, which is also connected to one end of the capacitor C8 to serve as the voltage output terminal of the second voltage regulator circuit. The other end of the capacitor C8 is grounded. The other end of the voltage divider resistor R8 is grounded.

2. The high-current screen driving circuit according to claim 1, characterized in that: The Boost circuit includes capacitor C1, inductor L1, diode D1, Boost power chip RTQ9297, voltage divider resistor R1, voltage divider resistor R2 and capacitor C2. The voltage input terminal of the Boost circuit is divided into three paths: one path is connected to one end of capacitor C1, one path is connected to pin 8 of the Boost power chip RTQ9297, and one path is connected to one end of inductor L1; the other end of capacitor C1 is grounded. The other end of the inductor L1 is divided into two paths: one path is connected to the LX pin of the Boost power chip RTQ9297, and the other path is connected to the positive terminal of the diode D1. The negative terminal of the diode D1 is connected to one end of the capacitor C2, and the other end of the capacitor C2 is grounded. The positive and negative terminals of the diode D1 serve as the output terminals of the Boost boost circuit. The voltage divider resistors R1 and R2 are connected in series to form a series voltage divider circuit; the series voltage divider point of the series voltage divider circuit is connected to pin 2 of the Boost power chip RTQ9297, the other end of the voltage divider resistor R1 is connected to the negative terminal of the diode D1, and the other end of the voltage divider resistor R2 is grounded.

3. The high-current screen driving circuit according to claim 2, characterized in that: The voltage multiplier circuit includes capacitor C3, capacitor C6, dual diodes D2 and D4, filter capacitor C4 and filter capacitor C7; One end of capacitor C3 is connected to the positive terminal of diode D1 in the Boost circuit, and the other end of capacitor C3 is connected to pin 3 of dual diode D2. Pin 1 of dual diode D2 is connected to the negative terminal of diode D1 in the Boost circuit. Pin 2 of dual diode D2 is connected to one end of filter capacitor C4, and the other end of filter capacitor C4 is grounded. One end of capacitor C6 is connected to the positive terminal of diode D1 in the Boost circuit, and the other end of capacitor C6 is connected to pin 3 of dual diode D4. Pin 2 of dual diode D4 is grounded, pin 1 of dual diode D4 is connected to one end of filter capacitor C7, and the other end of filter capacitor C7 is grounded.

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