TWI748716B - Gamma voltage genration circuit applied to vehicle source driving circuit - Google Patents

Abstract

A gamma voltage generation circuit, applied to a vehicle source driving circuit, includes a first/second external operational amplifier, a first/second ladder resistor string, a selector circuit, an internal operational amplifying circuit and a first/second protection circuit. The first and second external operational amplifier receive a first and second input voltage respectively and their output terminals is coupled to two terminals of first ladder resistor string. The selector circuit, coupled to the first ladder resistor string, provides divided voltages to the internal operational amplifying circuit. The second ladder resistor string, coupled to the internal operational amplifying circuit, outputs gamma voltages. The first protection circuit, coupled to output terminals of the first and second external operational amplifier, provides protection when the first and second input voltage are abnormal. The second protection circuit, coupled to the internal operational amplifying circuit, provides protection when the divided voltages are abnormal.

Description

Gamma voltage generating circuit applied to source driving circuit for vehicle

The present invention relates to a source drive circuit, and more particularly relates to a gamma voltage generating circuit applied to a source drive circuit for vehicles.

With the increasing importance of vehicle safety and the popularization of ISO26262, all vehicle systems on the market need to have functional safety as specified by ISO26262.

Please refer to FIG. 1. FIG. 1 illustrates a schematic diagram of a car source drive integrated circuit SIC applied to a car display panel PL. Generally speaking, the automotive safety integrity level (Automotive Safety Integrity Level, ASIL) of the automotive source drive integrated circuit SIC is inherited from its system, usually ASIL B level. In order to comply with the functional safety specified by ISO26262 and achieve the hardware quantitative index (Single Point Fault Metric, SPFM)/Latent Fault Metric (LFM)/hardware failure probability measurement above ASIL B level ( Probabilistic Metric for Hardware Failures (PMHF), each module (such as gamma voltage generating circuit) contained in the source drive integrated circuit SIC for vehicles needs to have a redundant design or a safety mechanism.

However, since the gamma voltage generating circuit in the traditional automotive source drive integrated circuit SIC usually does not have a safety mechanism, once any error occurs in the gamma voltage generating circuit, the gamma voltage provided by it will be abnormal. , Which in turn leads to the picture displayed on the car’s display panel Abnormal phenomena such as flashing screens or flashing lines appear on the surface, which seriously violates the functional safety specified by ISO26262, so further improvement is urgently needed.

In view of this, the present invention proposes a gamma voltage generating circuit applied to a source driving circuit for a vehicle to effectively solve the above-mentioned problems encountered in the prior art.

A specific embodiment according to the present invention is a gamma voltage generating circuit. In this embodiment, the gamma voltage generating circuit is applied to a source driving circuit for a vehicle. The gamma voltage generating circuit includes a first external operational amplifier, a second external operational amplifier, a first ladder resistor string, a selector circuit, an internal operational amplifier circuit, a second ladder resistor string, a first protection circuit, and a second protection circuit. One input terminal of the first external operational amplifier is coupled to the first input voltage, and the other input terminal and output terminal of the first external operational amplifier are coupled to each other. One input terminal of the second external operational amplifier is coupled to the second input voltage, and the other input terminal and output terminal of the second external operational amplifier are coupled to each other. The first ladder resistor string includes a plurality of resistors, which are connected in series between the output terminal of the first external operational amplifier and the output terminal of the second external operational amplifier. The selector circuit includes a plurality of selectors. Each of the selectors is correspondingly coupled to one end of each of the resistors to selectively provide a plurality of voltage divisions. The internal operational amplifier circuit includes a plurality of internal operational amplifiers. One input terminal of each internal operational amplifier of the internal operational amplifiers respectively receives one of the divided voltages, and the other input terminal and output terminal of each internal operational amplifier are coupled to each other. The second ladder resistor string includes a plurality of resistors, which are connected in series between the output terminal of one of the internal operational amplifiers and the output terminal of the other internal operational amplifier to respectively output a plurality of gamma voltages. The first protection circuit is respectively coupled to the output terminal of the first external operational amplifier and the output terminal of the second external operational amplifier for judging whether the first input voltage and the second input voltage are abnormal, and according to the judgment result If you decide whether to provide protection. The second protection circuit is respectively coupled to the output terminals of the internal operational amplifiers for judging whether the multiple voltages output by the internal operational amplifiers are abnormal, so as to determine whether to provide protection according to the judgment result.

In one embodiment, the vehicle source driving circuit is coupled to the vehicle display panel and drives the vehicle display panel to display images.

In one embodiment, when any error occurs in the gamma voltage generating circuit in the vehicle source driving circuit, the gamma voltage generating circuit activates its safety mechanism, so that the picture displayed on the vehicle display panel does not appear Splash screen or flash line to meet specific specifications.

In one embodiment, the specific specification is the ISO26262 specification.

In one embodiment, when the first input voltage is higher than the preset maximum voltage value, the first protection circuit determines that the first input voltage is an abnormal overvoltage and provides overvoltage protection; when the first input voltage is lower than the preset minimum voltage When the value is set, the first protection circuit determines that the first input voltage is abnormal under-voltage and provides under-voltage protection, and the preset maximum voltage value is higher than the preset minimum voltage value.

In one embodiment, when the second input voltage is higher than the preset maximum voltage value, the first protection circuit determines that the second input voltage is an abnormal overvoltage and provides overvoltage protection; when the second input voltage is lower than the preset minimum voltage When the value is set, the first protection circuit determines that the second input voltage is abnormal under-voltage and provides under-voltage protection, and the preset maximum voltage value is higher than the preset minimum voltage value.

In one embodiment, when at least one of the voltages output by the internal operational amplifiers is higher than a preset maximum voltage value, the second protection circuit determines that the at least one voltage is abnormal overvoltage and provides overvoltage protection; When the at least one voltage is lower than the predetermined minimum voltage value, the second protection circuit determines that the at least one voltage is abnormal under voltage and provides undervoltage protection; wherein the predetermined maximum voltage value is higher than the predetermined minimum voltage value.

In one embodiment, the second input voltage is lower than the first input voltage.

In one embodiment, the gamma voltage generating circuit further includes a register circuit, which is respectively coupled to the selectors in the selector circuit for controlling the operation of the selectors respectively.

Another specific embodiment according to the present invention is a gamma voltage generating circuit. In this embodiment, the gamma voltage generating circuit is applied to a source driving circuit for a vehicle. The gamma voltage generating circuit includes a first external operational amplifier, a second external operational amplifier, a first ladder resistor string, a selector circuit, an internal operational amplifier circuit, a second ladder resistor string, a first comparison circuit and a second comparison circuit. One input terminal of the first external operational amplifier is coupled to the first input voltage, and the other input terminal and output terminal of the first external operational amplifier are coupled to each other. One input terminal of the second external operational amplifier is coupled to the second input voltage, and the other input terminal and output terminal of the second external operational amplifier are coupled to each other. The first ladder resistor string includes a plurality of resistors, which are connected in series between the output terminal of the first external operational amplifier and the output terminal of the second external operational amplifier. The selector circuit includes a plurality of selectors. Each of the selectors is correspondingly coupled to one end of each of the resistors to selectively provide a plurality of voltage divisions. The internal operational amplifier circuit includes a plurality of internal operational amplifiers. One input terminal of each internal operational amplifier of the internal operational amplifiers respectively receives one of the divided voltages, and the other input terminal and output terminal of each internal operational amplifier are coupled to each other. The second ladder resistor string includes a plurality of resistors, which are connected in series between the output terminal of one of the internal operational amplifiers and the output terminal of the other internal operational amplifier to respectively output a plurality of gamma voltages. The first comparison circuit is respectively coupled to the output terminal of the first external operational amplifier and the output terminal of the second external operational amplifier to compare the first input voltage and the second input voltage and determine whether there is an abnormal voltage. The second comparison circuit includes a plurality of comparison units, which are sequentially coupled to the internal operational amplifiers The output terminals of the two adjacent internal operational amplifiers are used to determine whether the output voltage of the internal operational amplifiers is monotonically increasing or decreasing in sequence.

Compared with the prior art, the present invention proposes a corresponding safety mechanism for the gamma voltage generating circuit applied to the source driving circuit for vehicles. It detects errors in the gamma voltage generating circuit and informs the front end through physical pins. The system enters the Safety State to meet the functional safety requirements of the ISO26262 standard and reach the hardware quantitative index of the ASIL B level and above.

The advantages and spirit of the present invention can be further understood from the following detailed description of the invention and the accompanying drawings.

PL: car display panel

DA: display area

SIC: Automotive source drive integrated circuit

GIC: Automotive gate drive integrated circuit

3: Gamma voltage generating circuit

300: The first external operational amplifier

301: Second external operational amplifier

31: The first ladder resistor string

32: selector circuit

33: Internal operational amplifier circuit

34: Second ladder resistor string

35: The first protection circuit

36: The second protection circuit

37: register circuit

VINPH: first input voltage

VINPL: second input voltage

+, -: input terminal

320~32X: selector

330~33X: Internal operational amplifier

RE0~REX: resistance

RI0~RI(X-1): Resistance

VINP0~VINPX: partial pressure

REG0~REGX: Register signal

REGM, REGH, REGL: registered signal

V0~V255: output voltage

VGMPHO, VGMPLO: output signal

VGMPHI, VGMPLI: Input signal

OVPEH, OVPEL, OVPI0~OVPIX: preset maximum voltage value (overvoltage protection)

UVPEH, UVPEL, UVPI0~UVPIX: preset minimum voltage value (undervoltage protection)

Y: Number of signals

2 ^Y : Number of signals

4: Gamma voltage generating circuit

400: The first external operational amplifier

401: second external operational amplifier

41: The first ladder resistor string

42: selector circuit

420~42X: selector

43: Internal operational amplifier circuit

430~43X: Internal operational amplifier

44: Second ladder resistor string

45: The first comparison circuit

46: The second comparison circuit

461~46(X-1): Comparison unit

REG0/1~REG(X-1)/X: Register signal

5: One-bit comparator

M1~M6: Transistor switch

CS: current source

GND: ground terminal

OUT: output terminal

V(M-1): Voltage

VM: Voltage

The drawings of the present invention are described as follows: FIG. 1 shows a schematic diagram of a car source drive integrated circuit SIC applied to a car display panel PL.

2 is a schematic diagram of a gamma voltage generating circuit applied to a source driving circuit for a vehicle according to a preferred embodiment of the present invention.

3 is a schematic diagram of a gamma voltage generating circuit applied to a source driving circuit for a vehicle according to another preferred embodiment of the present invention.

FIG. 4 illustrates an embodiment of the comparison unit as a one-bit comparator.

Reference will now be made in detail to exemplary embodiments of the present invention, and examples of the exemplary embodiments are illustrated in the accompanying drawings. Elements/components with the same or similar numbers used in the drawings and embodiments are used to represent the same or similar parts.

A specific embodiment according to the present invention is a gamma voltage generating circuit. Here In the embodiment, the gamma voltage generating circuit is applied to a source driving circuit for a vehicle. The vehicle source driving circuit is coupled to the vehicle display panel and drives the vehicle display panel to display images. When any error occurs in the gamma voltage generating circuit in the car source driving circuit, the gamma voltage generating circuit will activate its safety mechanism, so that the screen displayed on the car display panel will not appear flickering screen or flickering line. To comply with ISO26262 specifications.

FIG. 2 shows a schematic diagram of a gamma voltage generating circuit applied to a source driving circuit for a vehicle in this embodiment.

As shown in FIG. 2, the gamma voltage generating circuit 3 is applied to a source driving circuit SIC for a vehicle. The gamma voltage generating circuit 3 includes a first external operational amplifier 300, a second external operational amplifier 301, a first ladder resistor string 31, a selector circuit 32, an internal operational amplifier circuit 33, a second ladder resistor string 34, and a first protection circuit 35. The second protection circuit 36 and the register circuit 37.

One input terminal + of the first external operational amplifier 300 is coupled to the first input voltage VINPH and the other input terminal-and its output terminal are coupled to each other. One input terminal + of the second external operational amplifier 301 is coupled to the second input voltage VINPL and the other input terminal-and its output terminal are coupled to each other. In this embodiment, the second input voltage VINPL is lower than the first input voltage VINPH.

The first ladder resistor string 31 includes a plurality of resistors RE0~REX. The resistors RE0-REX are connected in series between the output terminal of the first external operational amplifier 300 and the output terminal of the second external operational amplifier 301.

The selector circuit 32 includes a plurality of selectors 320 to 32X. Each of the selectors 320 to 32X is correspondingly coupled to one end of each of the resistors RE0 to REX to selectively provide a plurality of divided voltages VINP0 to VINPX. The register circuit 37 is respectively coupled to the selectors 320~32X in the selector circuit 32 for controlling the selectors respectively 320~32X operation.

The internal operational amplifier circuit 33 includes a plurality of internal operational amplifiers 330 to 33X. One input terminal of each of the internal operational amplifiers 330~33X respectively receives one of the divided voltages VINP0~VINPX, and the other input terminal and output terminal of each internal operational amplifier are coupled to each other .

The second ladder resistor string 34 includes a plurality of resistors RI1~RI(X-1), which are connected in series with the output terminal of one of the internal operational amplifiers 330~33X and the output terminal of the internal operational amplifier 331 and the other internal operational amplifier 33(X -1) between the output terminals to output a plurality of gamma voltages respectively.

The first protection circuit 35 is respectively coupled to the output terminal of the first external operational amplifier 300 and the output terminal of the second external operational amplifier 301 to compare the first input voltage VINPH with the second input voltage VINPL and determine whether there is an abnormal voltage , And then decide whether to provide protection.

In practical applications, the first protection circuit 35 can compare the first input voltage VINPH with the preset maximum voltage value OVPEH and the preset minimum voltage value UVPEH to determine whether the first input voltage VINPH is abnormal, and then determine whether the first input voltage VINPH is abnormal according to the determination result. Provide protection. Among them, the preset highest voltage value OVPEH is higher than the preset lowest voltage value UVPEH.

For example, when the first input voltage VINPH is higher than the preset maximum voltage value OVPEH, the first protection circuit 35 determines that the first input voltage VINPH is an abnormal overvoltage and provides overvoltage protection (OVP); When the input voltage VINPH is lower than the preset minimum voltage value UVPEH, the first protection circuit 35 determines that the first input voltage VINPH is abnormal under voltage and provides under voltage protection (UVP).

Similarly, the first protection circuit 35 can compare the second input voltage VINPL with the preset maximum voltage value OVPEL and the preset minimum voltage value UVPEL to determine the second input voltage Whether VINPL is abnormal, and then decide whether to provide protection according to the judgment result. Among them, the preset maximum voltage value OVPEL is higher than the preset minimum voltage value UVPEL.

When the second input voltage VINPL is higher than the preset maximum voltage value OVPEL, the first protection circuit 35 determines that the second input voltage VINPL is an abnormal overvoltage and provides overvoltage protection; when the second input voltage VINPL is lower than the preset minimum voltage value In the case of UVPEL, the first protection circuit 35 determines that the second input voltage VINPL is an under-voltage abnormality and provides under-voltage protection.

The second protection circuit 36 is respectively coupled to the output terminals of the internal operational amplifiers 330~33X to determine whether the voltages V255~V0 respectively output by the internal operational amplifiers 330~33X are abnormal, so as to determine whether to provide protection according to the judgment result .

In practical applications, the second protection circuit 36 can compare the voltage V255~V0 output by the internal operational amplifiers 330~33X with the preset maximum voltage value OVPI0~OVPIX and the preset minimum voltage value UVPI0~UVPIX, respectively, to determine Whether the voltages V255~V0 output by the internal operational amplifiers 330~33X are abnormal, and then determine whether to provide protection according to the judgment result. Among them, the preset maximum voltage value OVPI0~OVPIX will be higher than the respective preset minimum voltage value UVPI0~UVPIX.

For example, when the voltage V255 output by the internal operational amplifier 330 is higher than the preset maximum voltage value OVPI0, the second protection circuit 36 determines that the voltage V255 output by the internal operational amplifier 330 is overvoltage abnormal and provides overvoltage protection; When the voltage V255 output by the amplifier 330 is lower than the preset minimum voltage value UVPI0, the second protection circuit 36 determines that the voltage V255 output by the internal operational amplifier 330 is under-voltage abnormal and provides under-voltage protection. The rest can be deduced by analogy, so I won't repeat it here.

Another specific embodiment according to the present invention is a gamma voltage generating circuit. At In this embodiment, the gamma voltage generating circuit is applied to a source driving circuit for vehicles. The vehicle source driving circuit is coupled to the vehicle display panel and drives the vehicle display panel to display images. When any error occurs in the gamma voltage generating circuit in the car source driving circuit, the gamma voltage generating circuit will activate its safety mechanism, so that the screen displayed on the car display panel will not appear flickering screen or flickering line. In order to comply with specific specifications, such as ISO26262 specifications, but not limited to this.

Please refer to FIG. 3. FIG. 3 is a schematic diagram of a gamma voltage generating circuit applied to a source driving circuit for a vehicle in this embodiment.

As shown in FIG. 3, the gamma voltage generating circuit 4 includes a first external operational amplifier 400, a second external operational amplifier 401, a first ladder resistor string 41, a selector circuit 42, an internal operational amplifier circuit 43, and a second ladder resistor string. 44. The first comparison circuit 45 and the second comparison circuit 46.

One input terminal + of the first external operational amplifier 400 is coupled to the first input voltage VINPH and the other input terminal-and its output terminal are coupled to each other. One input terminal + of the second external operational amplifier 401 is coupled to the second input voltage VINPL and the other input terminal-and its output terminal are coupled to each other.

The first ladder resistor string 41 includes a plurality of resistors RE0~REX, which are connected in series between the output terminal of the first external operational amplifier 400 and the output terminal of the second external operational amplifier 401.

The selector circuit 42 includes a plurality of selectors 420 to 42X. Each of the selectors 420~42X is correspondingly coupled to one end of each of the resistors RE0~REX in the first ladder resistor string 41 to selectively provide a plurality of divided voltages VINP0~ VINPX.

The internal operational amplifier circuit 43 includes a plurality of internal operational amplifiers 430 to 43X. One of the input terminals of each of the internal operational amplifiers 430~43X respectively receives one of the divided voltages VINP0~VINPX, and the other input terminal and output terminal of each internal operational amplifier are coupled to each other .

The second ladder resistor string 44 includes a plurality of resistors RI1~RI(X-1), which are connected in series with the output terminal of one of the internal operational amplifiers 430~43X and the output terminal of the internal operational amplifier 431 and the other internal operational amplifier 43(X -1) between the output terminals to output a plurality of gamma voltages respectively.

The first comparison circuit 45 is respectively coupled to the output terminal of the first external operational amplifier 400 and the output terminal of the second external operational amplifier 401 to compare the first input voltage VINPH with the second input voltage VINPL and determine whether there is a voltage abnormality based on it , And then decide whether to provide protection.

In practical applications, the first comparison circuit 45 can compare the first input voltage VINPH with the preset highest voltage value and the preset lowest voltage value to determine whether the first input voltage VINPH is abnormal. Among them, the preset highest voltage value is higher than the preset lowest voltage value.

The second comparison circuit 46 includes a plurality of comparison units 461 to 46 (X-1), which are sequentially coupled to the output terminals of two adjacent internal operational amplifiers among the internal operational amplifiers 430 to 43X to determine the Whether the voltages V255~V0 output by the internal operational amplifiers 430~43X are monotonically increasing or decreasing in sequence, and whether to provide protection is determined according to the judgment result.

For example, the internal operational amplifiers 430 to 43X sequentially include internal operational amplifiers 430, 431, and 432, and the output terminals of the internal operational amplifiers 430, 431, and 432 output voltages V255, V254, and V253, respectively; the comparison units 461~46(X-1) sequentially include comparison units 461 and 462; the comparison unit 461 is coupled to the output terminal of the internal operational amplifier 430 and the output terminal of the internal operational amplifier 431 to compare the internal operational amplifier 430 and the internal operational amplifier 431 Respectively output the voltages V255 and V254 to generate the first comparison result and output the register signal REG0/1; The comparing unit 462 is coupled to the output terminal of the internal operational amplifier 431 and the output terminal of the internal operational amplifier 432 to compare the voltages V254 and V253 respectively output by the internal operational amplifier 431 and the internal operational amplifier 432 to generate a second comparison result and output the register Signal REG1/2.

It should be noted that the first comparison result provided by the register signal REG0/1 output by the comparison unit 461 and the second comparison result provided by the register signal REG1/2 output by the comparison unit 462 can be used to determine the internal operational amplifiers 430-432. Whether the output voltage V255~V253 is monotonically increasing or decreasing in sequence can be divided into the following three situations for explanation.

If the first comparison result of the comparison unit 461 is that the voltage V255 is higher than the voltage V254 and the second comparison result of the comparison unit 462 is that the voltage V254 is higher than the divided voltage V253, the voltages V255~V253 output by the internal operational amplifiers 430~432 will be It is judged to be sequentially and monotonously decreasing, so as to confirm that the internal operational amplifiers 430~432 should be normal, so there is no need to activate the protection mechanism.

If the first comparison result of the comparison unit 461 is that the voltage V255 is lower than the voltage V254 and the second comparison result of the comparison unit 462 is that the voltage V254 is lower than the divided voltage V253, the voltages V255~V253 output by the internal operational amplifiers 430~432 will be It is judged to be monotonously increasing in order to confirm that the internal operational amplifiers 430 to 432 should be normal, so there is no need to activate the protection mechanism.

If the first comparison result of the comparison unit 461 is that the voltage V255 is lower than the voltage V254, but the second comparison result of the comparison unit 462 is that the voltage V254 is higher than the divided voltage V253, or if the first comparison result of the comparison unit 461 is that the voltage V255 is higher At the voltage V254, but the second comparison result of the comparison unit 462 is that the voltage V254 is lower than the divided voltage V253, the voltages V255~V253 output by the internal operational amplifiers 430~432 will be judged as non-sequential monotonically increasing or monotonically decreasing (also That is, the occurrence of the gamma voltage reversal phenomenon), it means that at least one of the internal operational amplifiers 430 to 432 is abnormal, so the protection mechanism needs to be activated.

In practical applications, the comparison units 461 to 46 (X-1) in the first comparison circuit 45 and the second comparison circuit 46 may use a comparator circuit such as a 1-bit comparator, but Not limited to this.

For example, as shown in FIG. 4, the one-bit comparator 5 may include transistor switches M1 to M6 and a current source CS. The current source CS is respectively coupled to the transistor switches M1 and M2. The gate of the transistor switch M1 is coupled to the voltage V(M-1) and the gate of the transistor switch M2 is coupled to the voltage VM. The transistor switch M3 is coupled between the transistor switch M1 and the ground terminal GND. The transistor switch M4 is coupled between the transistor switch M2 and the ground terminal GND, and the gates of the transistor switches M3 and M5 are coupled to each other. The transistor switch M5 is coupled between the transistor switch M1 and the ground terminal GND. The transistor switch M6 is coupled between the transistor switch M2 and the ground terminal GND, and the gates of the transistor switches M5 and M6 are coupled to each other. The output terminal OUT of the one-bit comparator 5 is located between the transistor switches M2 and M6.

It should be noted that the one-bit comparator 5 shown in FIG. 4 is only an embodiment, and the comparison units 461-46 (X -1) Other types of comparison circuits can also be used, and it is not limited to this.

Compared with the prior art, the present invention proposes a corresponding safety mechanism for the gamma voltage generating circuit applied to the source driving circuit for vehicles. It detects errors in the gamma voltage generating circuit and informs the front end through physical pins. The system enters the Safety State to meet the functional safety requirements of the ISO26262 standard and reach the hardware quantitative index of the ASIL B level and above.

3: Gamma voltage generating circuit

300: The first external operational amplifier

301: Second external operational amplifier

31: The first ladder resistor string

32: selector circuit

33: Internal operational amplifier circuit

34: Second ladder resistor string

35: The first protection circuit

36: The second protection circuit

37: register circuit

VINPH: first input voltage

VINPL: second input voltage

+, -: input terminal

320~32X: selector

330~33X: Internal operational amplifier

RE0~REX: resistance

RI0~RI(X-1): Resistance

VINP0~VINPX: partial pressure

REG0~REGX: register signal

REGM, REGH: registered signal

V0~V255: output voltage

VGMPHO, VGMPLO: output signal

VGMPHI, VGMPLI: Input signal

OVPEH, OVPEL: preset maximum voltage value (overvoltage protection)

OVPI0~OVPIX: preset maximum voltage value (overvoltage protection)

UVPEH, UVPEL: preset minimum voltage value (undervoltage protection)

UVPI0~UVPIX: preset minimum voltage value (undervoltage protection)

Y: Number of signals

2 ^Y : Number of signals

Claims (20)

A gamma voltage generating circuit, applied to a source driving circuit for vehicles, includes: a first external operational amplifier, one input terminal of which is coupled to a first input voltage, and the other input terminal and its output terminal are mutually connected Coupled; a second external operational amplifier, one input terminal of which is coupled to a second input voltage and the other input terminal and its output terminal coupled to each other; a first ladder resistor string, including a plurality of resistors, connected to each other in series Between the output terminal of the first external operational amplifier and the output terminal of the second external operational amplifier; a selector circuit includes a plurality of selectors, each of the selectors is correspondingly coupled to the One end of each resistor of the resistor is used to selectively provide a plurality of voltage divisions; an internal operational amplifier circuit includes a plurality of internal operational amplifiers, and one of the input terminals of each internal operational amplifier of the internal operational amplifiers receives the One of the divided voltages is divided and the other input terminal and output terminal of each internal operational amplifier are coupled to each other; a second ladder resistor string, including a plurality of resistors, is connected in series to one of the internal operational amplifiers Between the output terminal of the internal operational amplifier and the output terminal of another internal operational amplifier to output a plurality of gamma voltages respectively; a first protection circuit is respectively coupled to the output terminal of the first external operational amplifier and the second external The output terminal of the operational amplifier is used to determine whether the first input voltage and the second input voltage are abnormal, so as to determine whether to provide protection according to the judgment result; and a second protection circuit is respectively coupled to the output terminals of the internal operational amplifiers, It is used to judge whether the partial pressures are abnormal, and to decide whether to provide protection according to the judgment result. According to the gamma voltage generating circuit described in item 1 of the scope of patent application, the vehicle source driving circuit is coupled to a vehicle display panel and drives the vehicle display panel to display a screen. The gamma voltage generating circuit described in item 2 of the scope of patent application, wherein when any error occurs in the gamma voltage generating circuit in the vehicle source driving circuit, the gamma voltage generating circuit will activate its safety Mechanism, so that the screen displayed on the vehicle display panel does not appear splash screen or flash line, in order to comply with a specific specification. For the gamma voltage generating circuit described in item 3 of the scope of patent application, the specific specification is the ISO26262 specification. According to the gamma voltage generating circuit described in item 1 of the scope of patent application, when the first input voltage is higher than a preset maximum voltage value, the first protection circuit determines that the first input voltage is an abnormal overvoltage and provides Over-voltage protection; when the first input voltage is lower than a preset minimum voltage value, the first protection circuit determines that the first input voltage is an abnormal under-voltage and provides the under-voltage protection, and the preset maximum voltage value is higher than The preset minimum voltage value. For the gamma voltage generating circuit described in item 1 of the scope of patent application, when the second input voltage is higher than a preset maximum voltage value, the first protection circuit determines that the second input voltage is abnormal over-voltage and provides The over-voltage protection; when the second input voltage is lower than a preset minimum voltage value, the first protection circuit determines that the second input voltage is abnormal under-voltage and provides under-voltage protection, the preset maximum voltage value is higher than The preset minimum voltage value. According to the gamma voltage generating circuit described in item 1 of the scope of patent application, when at least one of the divided voltages is higher than a preset maximum voltage value, the second protection circuit determines that the at least one divided voltage is The over-voltage is abnormal and provides over-voltage protection; when the at least one partial voltage is lower than a preset At the lowest voltage value, the second protection circuit determines that the at least one partial voltage is an abnormal undervoltage and provides undervoltage protection; wherein, the preset maximum voltage value is higher than the preset minimum voltage value. According to the gamma voltage generating circuit described in claim 1, wherein the second input voltage is lower than the first input voltage. For example, the gamma voltage generating circuit described in item 1 of the scope of patent application further includes: a register circuit, respectively coupled to the selectors in the selector circuit, for controlling the selectors of the selectors. Operation. A gamma voltage generating circuit, applied to a source driving circuit for vehicles, includes: a first external operational amplifier, one input terminal of which is coupled to a first input voltage, and the other input terminal and its output terminal are mutually connected Coupled; a second external operational amplifier, one input terminal of which is coupled to a second input voltage and the other input terminal and its output terminal coupled to each other; a first ladder resistor string, including a plurality of resistors, connected to each other in series Between the output terminal of the first external operational amplifier and the output terminal of the second external operational amplifier; a selector circuit includes a plurality of selectors, each of the selectors is correspondingly coupled to the One end of each resistor of the resistor is used to selectively provide a plurality of voltage divisions; an internal operational amplifier circuit includes a plurality of internal operational amplifiers, and one of the input terminals of each internal operational amplifier of the internal operational amplifiers receives the One of the divided voltages is divided and the other input terminal and output terminal of each internal operational amplifier are coupled to each other; A second ladder resistor string includes a plurality of resistors, which are connected in series between the output terminal of one of the internal operational amplifiers and the output terminal of the other internal operational amplifier to output a plurality of gamma voltages respectively ; A first comparison circuit, respectively coupled to the output terminal of the first external operational amplifier and the output terminal of the second external operational amplifier for comparing the first input voltage and the second input voltage and to determine whether there is a voltage Abnormal; and a second comparison circuit, including a plurality of comparison units, sequentially coupled to the output terminals of the two adjacent internal operational amplifiers in the internal operational amplifiers, to determine whether the internal operational amplifiers output voltage according to The order is monotonously increasing or monotonously decreasing. According to the gamma voltage generating circuit described in item 10 of the scope of patent application, the vehicle source driving circuit is coupled to a vehicle display panel and drives the vehicle display panel to display a screen. The gamma voltage generating circuit described in item 11 of the scope of patent application, wherein when any error occurs in the gamma voltage generating circuit in the vehicle source driving circuit, the gamma voltage generating circuit will activate its safety Mechanism, so that the screen displayed on the vehicle display panel does not appear splash screen or flash line, in order to comply with a specific specification. For the gamma voltage generating circuit described in item 12 of the scope of patent application, the specific specification is the ISO26262 specification. According to the gamma voltage generating circuit described in item 10 of the scope of patent application, the first comparison circuit is a 1-bit comparator. In the gamma voltage generating circuit described in item 10 of the scope of patent application, the comparison units in the second comparison circuit are all one-bit comparators. In the gamma voltage generating circuit described in item 10 of the scope of patent application, the internal operational amplifiers sequentially include a first internal operational amplifier, a second internal operational amplifier, and a third internal operational amplifier, and the first The output terminals of the internal operational amplifier, the second internal operational amplifier and the third internal operational amplifier respectively output a first voltage, a second voltage and a third voltage; the comparison units sequentially include a first comparison unit and A second comparison unit; the first comparison unit is coupled to the output terminal of the first internal operational amplifier and the output terminal of the second internal operational amplifier for comparing the first voltage with the second voltage to generate a first Comparison result; the second comparison unit is coupled to the output terminal of the second internal operational amplifier and the output terminal of the third internal operational amplifier for comparing the second voltage with the third voltage to generate a second comparison result. The gamma voltage generating circuit described in item 16 of the scope of patent application, wherein the first comparison result and the second comparison result are used to determine whether the first voltage, the second voltage, and the third voltage are sequentially monotonic Increase or decrease monotonically. The gamma voltage generating circuit according to item 17 of the scope of patent application, wherein if the first comparison result is that the first voltage is higher than the second voltage and the second comparison result is that the second voltage is higher than the third voltage Voltage, the first voltage, the second voltage, and the third voltage are determined to be sequentially monotonically decreasing, so as to confirm that the first internal operational amplifier, the second internal operational amplifier, and the third internal operational amplifier are normal. The gamma voltage generating circuit according to item 17 of the scope of patent application, wherein if the first comparison result is that the first voltage is lower than the second voltage and the second comparison result is that the second voltage is lower than the third voltage Voltage, the first voltage, the second voltage, and the third voltage are determined to be monotonically increasing sequentially, so as to confirm that the first internal operational amplifier and the second internal operational amplifier And the third internal operational amplifier has no abnormalities. For the gamma voltage generating circuit described in claim 17, wherein if the first comparison result is that the first voltage is lower than the second voltage, but the second comparison result is that the second voltage is higher than the first voltage Three voltages, or the first comparison result is that the first voltage is higher than the second voltage, but the second comparison result is that the second voltage is lower than the third voltage, the first voltage, the second voltage, and the If the third voltage is determined not to monotonically increase or decrease in sequence, at least one of the first internal operational amplifier, the second internal operational amplifier, and the third internal operational amplifier is abnormal.

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