Voltage rebound compensation circuit and display device

Abstract

The invention provides a voltage rebound compensation circuit and a display device.The voltage rebound compensation circuit comprises a state storage circuit, a power failure detection circuit and a starting voltage output circuit, and when power failure occurs and declined power supply voltage is larger than first reference voltage, first terminal voltage output by the state storage circuit is larger than second reference voltage, and the starting voltage output circuit outputs starting voltage. When the dropped power supply voltage is smaller than the first reference voltage, the first terminal voltage output by the state storage circuit is smaller than the second reference voltage, the starting voltage output circuit is switched to output the second starting voltage, and the first starting voltage is larger than the second starting voltage; therefore, the set starting voltage of the power management integrated circuit is improved in the power failure process, and when voltage rebound occurs, the power management integrated circuit is prevented from being restarted abnormally, so that picture abnormity or splash screen of the display panel is avoided, and the display effect is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of display devices, and particularly relates to a voltage bounce compensation circuit and a display device. Background Art

[0002] In a display device, a main board is usually used to supply a power supply voltage to a power management integrated circuit, and the power management integrated circuit provides a working power supply for a display panel and corresponding driving circuits.

[0003] During the shutdown process, the supply voltage gradually decreases, and the power management integrated circuit and the backend load stop working. Since the sudden power-off of the load will cause the supply voltage to bounce back, when the bounce-back voltage is too high, it will cause the power management integrated circuit to restart abnormally instantaneously, and then cause the display panel to power on abnormally, resulting in abnormal images or screen flashes on the display panel. Summary of the Invention

[0004] An object of the present invention is to provide a voltage bounce compensation circuit, aiming at solving the problem that in a traditional display device, voltage bounce during power-off causes abnormal restart of the power management integrated circuit, resulting in abnormal images or screen flashes on the display panel.

[0005] A first aspect of an embodiment of the present invention provides a voltage bounce compensation circuit, which is connected to a power management integrated circuit of a display device. The power input terminal of the power management integrated circuit is used to input a supply voltage, and the power management integrated circuit starts to work when the supply voltage is greater than the start voltage programmed at the start voltage terminal or greater than the initial start voltage. The voltage bounce compensation circuit includes: A state storage circuit, which is connected to the power input terminal of the power management integrated circuit. The state storage circuit is used to charge when the power management integrated circuit is initially powered on and output a first terminal voltage; A power-off detection circuit, which is respectively connected to the power input terminal of the power management integrated circuit and the state storage circuit. The power-off detection circuit is used to compare the supply voltage with a first reference voltage, and discharge the first terminal voltage when the supply voltage is less than the first reference voltage; A start voltage output circuit, which is respectively connected to the power input terminal of the power management integrated circuit, the start voltage terminal and the state storage circuit. The start voltage output circuit is used to compare the first terminal voltage with a second reference voltage; When the first terminal voltage is greater than the second reference voltage, program the first startup voltage to the startup voltage terminal of the power management integrated circuit; when the first terminal voltage is less than or equal to the second reference voltage, program the second startup voltage to the startup voltage terminal of the power management integrated circuit. The first startup voltage is greater than the second startup voltage, and the second startup voltage is greater than the initial startup voltage. And cut off the output of the corresponding startup voltage when there is no power supply voltage input to the power management integrated circuit.

[0006] Optionally, the state storage circuit includes a first diode and a first capacitor. The anode of the first diode is connected to the power input terminal of the power management integrated circuit. The cathode of the first diode and the first end of the first capacitor are connected to form the power output terminal of the state storage circuit, and the second end of the first capacitor is grounded.

[0007] Optionally, the power-off detection circuit includes: A power supply circuit, connected to the power input terminal of the power management integrated circuit, for charging and outputting a second terminal voltage when the power management integrated circuit is initially powered on. A first comparison circuit, connected to the power input terminal of the power management integrated circuit and the power supply circuit respectively, for comparing the power supply voltage with the first reference voltage, and outputting a first switch signal when the power supply voltage is greater than the first reference voltage, and outputting a second switch signal when the power supply voltage is less than or equal to the first reference voltage. A discharge circuit, connected between the state storage circuit and the ground, and also connected to the first comparison circuit. The discharge circuit is triggered by the first switch signal to turn off, and is triggered by the second switch signal to turn on and discharge the first terminal voltage.

[0008] Optionally, the power supply circuit includes a second diode and a second capacitor. The anode of the second diode is connected to the power input terminal of the power management integrated circuit. The cathode of the second diode and the first end of the second capacitor form the output terminal of the power supply circuit, and the second end of the second capacitor is grounded.

[0009] Optionally, the first comparison circuit includes a first zener diode and a first comparator. The inverting input terminal of the first comparator is connected to the power input terminal of the power management integrated circuit. The cathode of the first voltage regulator diode, the non-inverting input terminal of the first comparator, and the power input terminal of the power management integrated circuit are connected. The anode of the first voltage regulator diode is grounded. The power supply terminal of the first comparator is connected to the power output terminal of the power supply circuit. The output terminal of the first comparator forms the output terminal of the first comparison circuit.

[0010] Optionally, the discharge circuit includes a first resistor and a first electronic switch tube; The first end of the first resistor is connected to the output terminal of the first comparison circuit. The second end of the first resistor is connected to the control terminal of the first electronic switch tube. The first end of the first electronic switch tube is grounded. The second end of the first electronic switch tube is connected to the power output terminal of the state storage circuit.

[0011] Optionally, the start-up voltage output circuit includes: A second comparison circuit, which is respectively connected to the power input terminal of the power management integrated circuit and the state storage circuit. The second comparison circuit is used to compare the first terminal voltage with a second reference voltage, and outputs a first switching signal when the first terminal voltage is greater than the second reference voltage, outputs a second switching signal when the first terminal voltage is less than or equal to the second reference voltage, and cuts off the output of the corresponding switching signal when there is no power supply voltage input to the power management integrated circuit; A voltage switching output circuit, which is respectively connected to the second comparison circuit and the start-up voltage terminal of the power management integrated circuit. The voltage switching output circuit is used to switch and output the first start-up voltage when receiving the first switching signal, and switch and output the second start-up voltage when receiving the second switching signal.

[0012] Optionally, the second comparison circuit includes a second resistor, a second voltage regulator diode, and a second comparator; The first end of the second resistor is connected to the power output terminal of the state storage circuit. The second end of the second resistor is connected to the non-inverting input terminal of the second comparator. The cathode of the second voltage regulator diode, the power input terminal of the power management integrated circuit, and the inverting input terminal of the second comparator are connected. The power supply terminal of the second comparator is connected to the power input terminal of the power management integrated circuit. The anode of the second voltage regulator diode is grounded. The output terminal of the second comparator forms the signal output terminal of the second comparison circuit.

[0013] Optionally, the voltage switching output circuit includes a third resistor, a second electronic switch tube, and a third electronic switch tube; The first end of the third resistor is connected to the signal output end of the second comparison circuit. The second end of the third resistor, the control end of the second electronic switch tube, and the control end of the third electronic switch tube are connected. The first end of the second electronic switch tube is used to input the first startup voltage, the first end of the third electronic switch tube is used to input the second startup voltage, and the second ends of the second electronic switch tube and the third electronic switch tube are connected to form the power output end of the voltage switching output circuit.

[0014] In a second aspect of the embodiments of the present invention, a display device is proposed, which includes a power management integrated circuit and the voltage bounce compensation circuit as described above. The voltage bounce compensation circuit is respectively connected to the power input end and the startup voltage end of the power management integrated circuit.

[0015] The beneficial effects of the embodiments of the present invention compared with the prior art are as follows: The above voltage bounce compensation circuit includes a state storage circuit, a power-off detection circuit, and a startup voltage output circuit. When powered on normally, the supply voltage is greater than the initial startup voltage of the power management integrated circuit, and the power management integrated circuit works normally. When a power-off occurs, when the decreasing supply voltage is greater than the first reference voltage, the voltage at the first end output by the state storage circuit is greater than the second reference voltage, and the startup voltage output circuit switches to output the first startup voltage. When the decreasing supply voltage is less than the first reference voltage, the voltage at the first end output by the state storage circuit is less than the second reference voltage, and the startup voltage output circuit switches to output the second startup voltage. The first startup voltage is greater than the second startup voltage, so as to increase the set startup voltage of the power management integrated circuit during the power-off process and prevent the power management integrated circuit from restarting abnormally when a voltage bounce occurs, thereby avoiding abnormal pictures or screen flashes on the display panel and improving the display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a module schematic diagram of the voltage bounce compensation circuit provided in Embodiment 1 of the present invention; Figure 2 It is a signal waveform schematic diagram of the voltage bounce compensation circuit provided in Embodiment 1 of the present invention; Figure 3 It is a module schematic diagram of the voltage bounce compensation circuit provided in Embodiment 2 of the present invention; Figure 4 It is a circuit schematic diagram of the voltage bounce compensation circuit provided in Embodiment 3 of the present invention; Figure 5 It is a module schematic diagram of the display device provided in Embodiment 2 of the present invention.

[0017] Wherein, each reference numeral in the figure is: 100, Voltage bounce compensation circuit; 200, Power management integrated circuit; 10, Power-down detection circuit; 20, Status storage circuit; 30, Startup voltage output circuit; 11, Power supply circuit; 12, First comparison circuit; 13, Discharge circuit; 31, Second comparison circuit; 32, Voltage switching output circuit; R1, First resistor; R2, Second resistor; R3, Third resistor; C1, First capacitor; C2, Second capacitor; Q1, First electronic switch tube; Q2, Second electronic switch tube; Q3, Third electronic switch tube; U1, First comparator; U2, Second comparator; D1, First diode; D2, Second diode; ZD1, First voltage regulator diode; ZD2, Second voltage regulator diode; VCC, Power supply voltage; Vref1, First reference voltage; Vref2, Second reference voltage; V1, First terminal voltage; V2, Second terminal voltage; Vth0, Initial startup voltage; Vth1, First startup voltage; Vth2, Second startup voltage; Vin, Input voltage terminal; Vth, Startup voltage terminal. Detailed implementation manners

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0020] Embodiment 1 A first aspect of an embodiment of the present invention provides a voltage bounce compensation circuit 100, which is connected to a power management integrated circuit 200 of a display device. The power input terminal Vin of the power management integrated circuit 200 is used to input a power supply voltage VCC. The power management integrated circuit 200 starts to work when the power supply voltage VCC is greater than the startup voltage programmed at the startup voltage terminal Vth or greater than the initial startup voltage Vth0.

[0021] Among them, the power management integrated circuit 200 includes a power input terminal Vin, a startup voltage terminal Vth, and at least one power output terminal. The power input terminal Vin is used to connect to the main board and obtain the supply voltage VCC. The startup voltage terminal Vth is used to program the startup voltage. When the power management integrated circuit 200 is initially applied, the initial startup voltage Vth0 is programmed through the corresponding programming module as the threshold voltage set by default for the power management integrated circuit 200. When the power management integrated circuit 200 is restarted each time and there is no other startup voltage programming, it will default to applying the initial startup voltage Vth0 and compare it with the supply voltage VCC. When the supply voltage VCC is greater than the initial startup voltage Vth0, the power management integrated circuit 200 starts and outputs the working voltage to each module at the back end. For example, it outputs multiple working voltages to the timing controller, source driver circuit, gate driver circuit, and display panel in the display device, etc. The source driver circuit is used to output data signals under the control of the timing controller, the gate driver circuit is used to output scan signals under the control of the timing controller and scan the display panel line by line, and the display panel displays the corresponding image information under the drive of the data signal and the scan signal.

[0022] When a voltage bounce occurs, since the initial startup voltage Vth0 of the power management integrated circuit 200 is too small, the supply voltage VCC after the bounce is greater than the initial startup voltage Vth0, and the power management integrated circuit 200 restarts abnormally, resulting in the source driver circuit and the gate driver circuit abnormally outputting data signals and scan signals, and causing the display panel to display abnormal pictures or flash screens.

[0023] To solve this problem, in this embodiment, a voltage bounce compensation circuit 100 is proposed, which is used to program different sizes of startup voltages correspondingly when power is off, so that the supply voltage VCC is less than the programmed startup voltage when power is off, thereby preventing the power management integrated circuit 200 from restarting abnormally, avoiding abnormal pictures or flash screens on the display panel, and improving the display effect.

[0024] As Figure 1 shown, in this embodiment, the voltage bounce compensation circuit 100 includes: A state storage circuit 20, connected to the power input terminal Vin of the power management integrated circuit 20, and the state storage circuit 20 is used to charge when the power management integrated circuit 200 is initially powered on and output the first terminal voltage V1; A power-off detection circuit 10, connected to the power input terminal Vin of the power management integrated circuit 200 and the state storage circuit 20 respectively. The power-off detection circuit 10 is used to compare the supply voltage VCC with the first reference voltage Vref1, and discharge the first terminal voltage V1 when the supply voltage VCC is less than the first reference voltage Vref1; The startup voltage output circuit 30 is respectively connected to the power input terminal Vin, the startup voltage terminal Vth of the power management integrated circuit 200, and the status storage circuit 20. The startup voltage output circuit 30 is used to compare the first terminal voltage V1 and the second reference voltage Vref2; When the first terminal voltage V1 is greater than the second reference voltage Vref2, the first startup voltage Vth1 is programmed to the startup voltage terminal Vth of the power management integrated circuit 200. When the first terminal voltage V1 is less than or equal to the second reference voltage Vref2, the second startup voltage Vth2 is programmed to the startup voltage terminal Vth of the power management integrated circuit 200. The first startup voltage Vth1 is greater than the second startup voltage Vth2, and the second startup voltage Vth2 is greater than the initial startup voltage Vth0; And when there is no power supply voltage VCC input to the power management integrated circuit 200, the corresponding startup voltage output is cut off.

[0025] In this embodiment, refer to Figure 2 As shown, when the main board is normally powered on to output the power supply voltage VCC and the voltage bounce compensation circuit 100 has not output the startup voltage yet, the power management integrated circuit 200 first defaults to the set initial startup voltage Vth0, and compares the initial startup voltage Vth0 with the power supply voltage VCC. Assume that the power supply voltage VCC is 5V and the initial startup voltage Vth0 is 0.7V. Since the received power supply voltage VCC is greater than the initial startup voltage Vth0, the power management integrated circuit 200 starts to perform power conversion work and outputs the working voltage to the corresponding circuit modules at the back end.

[0026] The status storage circuit 20 is charged when powered on and outputs the first terminal voltage V1. Under normal conditions, the first terminal voltage V1 is greater than the second reference voltage Vref2. At this time, the startup voltage output circuit 30 switches to output the first startup voltage Vth1. Since the power management integrated circuit 200 only performs startup voltage detection when the power is turned off and then powered on again, even if the first startup voltage Vth1 is being programmed and output at this time, the power management integrated circuit 200 maintains the default initial startup voltage Vth0, and the power management integrated circuit 200 normally outputs the working voltage.

[0027] When powering off, the supply voltage VCC starts to drop. When the supply voltage VCC is less than the initial startup voltage Vth0, the power management integrated circuit 200, which is the load, shuts down and stops working. The load suddenly loses power, which may cause the problem of the supply voltage VCC bouncing back. For example, when the voltage A after the power-down bounce of the supply voltage VCC is greater than the first reference voltage Vref1, or when the voltage A after the power-down bounce of the supply voltage VCC is greater than zero and less than the first reference voltage Vref1. Assuming the first reference voltage Vref1 is 1V, the voltage A after the power-down bounce may be greater than the initial startup voltage Vth0, and there is a possibility that the power management integrated circuit 200 restarts, resulting in an abnormal display panel.

[0028] Therefore, during power-off, the power-down detection circuit 10 is used to compare the supply voltage VCC. When the supply voltage VCC with a power-down bounce is greater than the first reference voltage Vref1, the power-down detection circuit 10 does not discharge the first terminal voltage V1. The first terminal voltage V1 maintains a state greater than the second reference voltage Vref2. The startup voltage output circuit 30 switches to output the first startup voltage Vth1 and programs it into the power management integrated circuit 200. The first startup voltage Vth1 is greater than the first reference voltage Vref1 and greater than the supply voltage VCC with a power-down bounce. For example, the first startup voltage Vth1 can be set to 5V. At this time, the supply voltage VCC of the power management integrated circuit 200 is less than the reprogrammed first startup voltage Vth1, and the power management integrated circuit 200 does not start working. The power management integrated circuit 200 maintains the shutdown state and has no working voltage output. The corresponding source driver circuit and gate driver circuit have no signal output, and the display panel normally turns off the screen.

[0029] And when the supply voltage VCC with a power-down bounce is greater than zero and less than or equal to the first reference voltage Vref1, the power-down detection circuit 10 provides a discharge path and discharges the first terminal voltage V1 of the state storage circuit 20. The first terminal voltage V1 drops. When the first terminal voltage V1 is less than the second reference voltage Vref2, the startup voltage output circuit 30 switches to output the second startup voltage Vth2 and programs it into the power management integrated circuit 200. The second startup voltage Vth2 is greater than the first reference voltage Vref1. For example, the first startup voltage Vth1 is set to 1.1V. At this time, the supply voltage VCC of the power management integrated circuit 200 is less than the reprogrammed second startup voltage Vth2, and the power management integrated circuit 200 does not start working. The power management integrated circuit 200 maintains the shutdown state and has no working voltage output. The corresponding source driver circuit and gate driver circuit have no signal output, and the display panel normally turns off the screen, avoiding display abnormalities or screen flashing.

[0030] When the supply voltage VCC completely drops to zero, the start-up voltage output circuit 30 stops working, and no start-up voltage is programmed into the power management integrated circuit 200. Then, the power management integrated circuit 200 enables the initially programmed start-up voltage Vth0 by default during the next power-on and achieves normal start-up operation.

[0031] The state storage circuit 20 can adopt corresponding storage modules such as capacitors and batteries. The power-down detection circuit 10 can adopt corresponding comparison circuits, discharge circuits 13, etc. The start-up voltage output circuit 30 can adopt corresponding comparison circuits, voltage output circuits, etc. The specific structure is not limited.

[0032] The beneficial effects of the embodiments of the present invention compared with the prior art are as follows: The above-mentioned voltage bounce compensation circuit 100 includes a state storage circuit 20, a power-down detection circuit 10, and a start-up voltage output circuit 30. When powered on normally, the supply voltage VCC is greater than the initial start-up voltage Vth0 of the power management integrated circuit 200, and the power management integrated circuit 200 operates normally. When a power-down occurs, when the descending supply voltage VCC is greater than the first reference voltage Vref1, the first terminal voltage V1 output by the state storage circuit 20 is greater than the second reference voltage Vref2, and the start-up voltage output circuit 30 switches to output the first start-up voltage Vth1. When the descending supply voltage VCC is less than the first reference voltage Vref1, the first terminal voltage V1 output by the state storage circuit 20 is less than the second reference voltage Vref2, and the start-up voltage output circuit 30 switches to output the second start-up voltage Vth2. The first start-up voltage Vth1 is greater than the second start-up voltage Vth2. Therefore, during the power-down process, the set start-up voltage of the power management integrated circuit 200 is increased. When a voltage bounce occurs, abnormal restart of the power management integrated circuit 200 is prevented, thereby avoiding abnormal display or screen flashing of the display panel and improving the display effect.

[0033] Embodiment 2 In an alternative embodiment, as Figure 3 shown, the power-down detection circuit 10 includes: A power supply circuit 11, connected to the power input terminal Vin of the power management integrated circuit 200, and the power supply circuit 11 is used to charge during the initial power-on of the power management integrated circuit 200 and output a second terminal voltage V2; A first comparison circuit 12, respectively connected to the power input terminal Vin of the power management integrated circuit 200 and the power supply circuit 11, for comparing the supply voltage VCC with the first reference voltage Vref1, and outputting a first switching signal when the supply voltage VCC is greater than the first reference voltage Vref1, and outputting a second switching signal when the supply voltage VCC is less than or equal to the first reference voltage Vref1; A discharge circuit 13 is connected between the state storage circuit 20 and the ground. The discharge circuit 13 is also connected to the first comparison circuit 12. The discharge circuit 13 is triggered to turn off by the first switch signal and is triggered to turn on by the second switch signal to discharge the first terminal voltage V1.

[0034] The start-up voltage output circuit 30 includes: A second comparison circuit 31 is respectively connected to the power input terminal Vin of the power management integrated circuit 200 and the state storage circuit 20. The second comparison circuit 31 is used to compare the first terminal voltage V1 with the second reference voltage Vref2. When the first terminal voltage V1 is greater than the second reference voltage Vref2, a first switching signal is output. When the first terminal voltage V1 is less than or equal to the second reference voltage Vref2, a second switching signal is output. And when there is no power supply voltage VCC input to the power management integrated circuit 200, the corresponding switching signal is cut off from being output; A voltage switching output circuit 32 is respectively connected to the second comparison circuit 31 and the start-up voltage terminal Vth of the power management integrated circuit 200. The voltage switching output circuit 32 is used to switch and output a first start-up voltage Vth1 when receiving the first switching signal and switch and output a second start-up voltage Vth2 when receiving the second switching signal.

[0035] In this embodiment, when the main board is normally powered on to output the power supply voltage VCC, the received power supply voltage VCC is greater than the initial start-up voltage Vth0. The power management integrated circuit 200 starts to perform power conversion work and outputs a working voltage to the corresponding circuit modules at the back end.

[0036] The power supply circuit 11 is charged when the power management integrated circuit 200 is normally powered on and outputs a second terminal voltage V2. The second terminal voltage V2 provides a stable working voltage for the first comparison circuit 12. The state storage circuit 20 is charged when powered on and outputs a first terminal voltage V1. At this time, the power supply voltage VCC is greater than the first reference voltage Vref1. The first comparison circuit 12 outputs a first switch signal. The discharge circuit 13 will maintain the off state when receiving the first switch signal and will not discharge the first terminal voltage V1 of the state storage circuit 20.

[0037] At this time, the first terminal voltage V1 is greater than the second reference voltage Vref2. The second comparison circuit 31 switches and outputs a first switching signal. The first switching signal controls the voltage switching output circuit 32 to output a first start-up voltage Vth1. Since the power management integrated circuit 200 only detects the start-up voltage when the power is turned off and then powered on again, even if the first start-up voltage Vth1 is being programmed and output at this time, the power management integrated circuit 200 maintains the default initial start-up voltage Vth0, and the power management integrated circuit 200 normally outputs a working voltage.

[0038] During power-off, the first comparison circuit 12 compares the supply voltage VCC. When the supply voltage VCC with power-off bounce is greater than the first reference voltage Vref1, the first comparison circuit 12 outputs a first switch signal, the discharge circuit 13 is turned off, and does not discharge the first terminal voltage V1. The first terminal voltage V1 maintains a state greater than the second reference voltage Vref2. The second comparison circuit 31 switches to output a first switching signal, and the voltage switching output circuit 32 switches to output a first start voltage Vth1, which is programmed into the power management integrated circuit 200. The first start voltage Vth1 is greater than the first reference voltage Vref1 and greater than the supply voltage VCC after power-off bounce. For example, the first start voltage Vth1 can be set to 5V. At this time, the supply voltage VCC of the power management integrated circuit 200 is less than the reprogrammed first start voltage Vth1, the power management integrated circuit 200 does not start working, the power management integrated circuit 200 maintains the shutdown state, has no working voltage output, and the corresponding source driver circuit and gate driver circuit have no signal output, and the display panel normally turns off the screen.

[0039] And when the supply voltage VCC with power-off bounce is greater than zero and less than or equal to the first reference voltage Vref1, the first comparison circuit 12 outputs a second switch signal, the discharge circuit 13 conducts to provide a discharge path, and discharges the first terminal voltage V1 of the state storage circuit 20. The first terminal voltage V1 drops. When the first terminal voltage V1 is less than the second reference voltage Vref2, the second comparison circuit 31 outputs a second switching signal, and the voltage switching output circuit 32 switches to output a second start voltage Vth2, which is programmed into the power management integrated circuit 200. The second start voltage Vth2 is greater than the first reference voltage Vref1. For example, the first start voltage Vth1 is set to 1.1V. At this time, the supply voltage VCC of the power management integrated circuit 200 is less than the reprogrammed second start voltage Vth2, the power management integrated circuit 200 does not start working, the power management integrated circuit 200 maintains the shutdown state, has no working voltage output, and the corresponding source driver circuit and gate driver circuit have no signal output, and the display panel normally turns off the screen, avoiding display anomalies or flashing.

[0040] And when the supply voltage VCC completely powers off to zero, the second comparison circuit 31 stops working, and the voltage switching output circuit 32 has no start voltage programmed into the power management integrated circuit 200. The power management integrated circuit 200 then enables the initially set start voltage Vth0 with default settings when powered on next time and realizes normal startup and operation.

[0041] The power supply circuit 11 can adopt corresponding storage circuits such as capacitors and batteries. The first comparison circuit 12 and the second comparison circuit 31 can adopt corresponding structures such as comparators and switching transistors. The discharge circuit 13 and the voltage switching output circuit 32 can adopt corresponding switching circuits, etc. The specific structure is not limited.

[0042] Embodiment 3 In an alternative embodiment, as Figure 4 shown, the state storage circuit 20 includes a first diode D1 and a first capacitor C1; The anode of the first diode D1 is connected to the power input terminal Vin of the power management integrated circuit 200. The cathode of the first diode D1 and the first end of the first capacitor C1 are connected to form the power output terminal of the state storage circuit 20, and the second end of the first capacitor C1 is grounded.

[0043] The power supply circuit 11 includes a second diode D2 and a second capacitor C2; The anode of the second diode D2 is connected to the power input terminal Vin of the power management integrated circuit 200. The cathode of the second diode D2 and the first end of the second capacitor C2 form the output terminal of the power supply circuit 11, and the second end of the second capacitor C2 is grounded.

[0044] The first comparison circuit 12 includes a first voltage regulator diode ZD1 and a first comparator U1; The inverting input terminal of the first comparator U1 is connected to the power input terminal Vin of the power management integrated circuit 200. The cathode of the first voltage regulator diode ZD1, the non-inverting input terminal of the first comparator U1, and the power input terminal Vin of the power management integrated circuit 200 are connected. The anode of the first voltage regulator diode ZD1 is grounded. The power supply terminal of the first comparator U1 is connected to the power output terminal of the power supply circuit 11, and the output terminal of the first comparator U1 forms the output terminal of the first comparison circuit 12.

[0045] The discharge circuit 13 includes a first resistor R1 and a first electronic switch tube Q1; The first end of the first resistor R1 is connected to the output terminal of the first comparison circuit 12. The second end of the first resistor R1 is connected to the control terminal of the first electronic switch tube Q1. The first end of the first electronic switch tube Q1 is grounded, and the second end of the first electronic switch tube Q1 is connected to the power output terminal of the state storage circuit 20.

[0046] The second comparison circuit 31 includes a second resistor R2, a second voltage regulator diode ZD2, and a second comparator U2; The first end of the second resistor R2 is connected to the power output terminal of the state storage circuit 20. The second end of the second resistor R2 is connected to the non-inverting input terminal of the second comparator U2. The cathode of the second voltage regulator diode ZD2, the power input terminal Vin of the power management integrated circuit 200, and the inverting input terminal of the second comparator U2 are connected. The anode of the second voltage regulator diode ZD2 is grounded. The power supply terminal of the second comparator U2 is connected to the power input terminal Vin of the power management integrated circuit 200, and the output terminal of the second comparator U2 forms the signal output terminal of the second comparison circuit 31.

[0047] The voltage switching output circuit 32 includes a third resistor R3, a second electronic switch tube Q2, and a third electronic switch tube Q3; The first end of the third resistor R3 is connected to the signal output end of the second comparison circuit 31. The second end of the third resistor R3, the control end of the second electronic switch tube Q2, and the control end of the third electronic switch tube Q3 are connected. The first end of the second electronic switch tube Q2 is used to input a first startup voltage Vth1, and the first end of the third electronic switch tube Q3 is used to input a second startup voltage Vth2. The second ends of the second electronic switch tube Q2 and the third electronic switch tube Q3 are connected to form the power output end of the voltage switching output circuit 32.

[0048] In this embodiment, when powered on normally, the supply voltage VCC charges the first capacitor C1 to the first terminal voltage V1 through the first diode D1. At this time, the first terminal voltage V1 is the difference between the supply voltage VCC and the forward voltage drop of the first diode D1. For example, when the supply voltage VCC is 5V and the voltage drop of the first diode D1 is 0.7V, then the first terminal voltage V1 is 4.3V.

[0049] Similarly, when powered on normally, the supply voltage VCC charges the second capacitor C2 to the second terminal voltage V2 through the second diode D2. The second terminal voltage V2 is the difference between the supply voltage VCC and the forward voltage drop of the second diode D2. For example, when the supply voltage VCC is 5V and the voltage drop of the second diode D2 is 0.7V, then the second terminal voltage V2 is 4.3V, and the second terminal voltage V2 provides a stable operating voltage for the first comparator U1.

[0050] The first reference voltage Vref1 is generated by the first voltage regulator diode ZD1. For example, the first reference voltage Vref1 is 1V.

[0051] The second reference voltage Vref2 is generated by the second voltage regulator diode ZD2. For example, the second reference voltage Vref2 is 2.5V.

[0052] When the motherboard normally outputs the supply voltage VCC, the received supply voltage VCC is greater than the initial startup voltage Vth0, and the power management integrated circuit 200 starts to perform power conversion work and outputs a working voltage to the corresponding circuit modules at the back end.

[0053] The second capacitor C2 is charged when the power management integrated circuit 200 is powered on normally and outputs the second terminal voltage V2. The second terminal voltage V2 provides a stable operating voltage for the first comparison circuit 12. The first capacitor C1 is charged when powered on and outputs the first terminal voltage V1. At this time, the supply voltage VCC is greater than the first reference voltage Vref1, and the first comparator U1 outputs a low-level first switching signal. The first electronic switch tube Q1 receives the first switching signal and will remain in the off state and will not discharge the first terminal voltage V1 of the first capacitor C1.

[0054] At this time, the first terminal voltage V1 is greater than the second reference voltage Vref2, and the second comparator U2 switches to output a first switching signal with a high level. The first switching signal controls the second electronic switch tube Q2 to conduct and output a first startup voltage Vth1. Since the power management integrated circuit 200 only detects the startup voltage when the power is turned off and then powered on again, even if the first startup voltage Vth1 is being programmed and output at this time, the power management integrated circuit 200 maintains the default initial startup voltage Vth0, and the power management integrated circuit 200 normally outputs the working voltage.

[0055] During power-off, the first comparator U1 compares the supply voltage VCC. When the supply voltage VCC with power-off bounce is greater than the first reference voltage Vref1, the first comparator U1 outputs a first switching signal with a low level, and the first electronic switch tube Q1 is turned off, without discharging the first terminal voltage V1. The first terminal voltage V1 maintains a state greater than the second reference voltage Vref2. The second comparator U2 switches to output a first switching signal with a high level, and the second electronic switch tube Q2 switches to output a first startup voltage Vth1, which is programmed into the power management integrated circuit 200. The first startup voltage Vth1 is greater than the first reference voltage Vref1 and greater than the supply voltage VCC after power-off bounce. For example, the first startup voltage Vth1 can be set to 5V. At this time, the supply voltage VCC of the power management integrated circuit 200 is less than the reprogrammed first startup voltage Vth1, the power management integrated circuit 200 does not start to work, the power management integrated circuit 200 maintains the shutdown state, without outputting the working voltage, and the corresponding source driver circuit and gate driver circuit do not output signals, and the display panel normally turns off the screen.

[0056] And when the supply voltage VCC with power-off bounce is greater than zero and less than or equal to the first reference voltage Vref1, the first comparator U1 outputs a second switching signal with a high level, the first electronic switch tube Q1 conducts to provide a discharge path, and discharges the first terminal voltage V1. The first terminal voltage V1 decreases. When the first terminal voltage V1 is less than the second reference voltage Vref2, the second comparator U2 outputs a second switching signal with a low level, and the third electronic switch tube Q3 switches to output a second startup voltage Vth2, which is programmed into the power management integrated circuit 200. The second startup voltage Vth2 is greater than the first reference voltage Vref1. For example, the first startup voltage Vth1 is set to 1.1V. At this time, the supply voltage VCC of the power management integrated circuit 200 is less than the reprogrammed second startup voltage Vth2, the power management integrated circuit 200 does not start to work, the power management integrated circuit 200 maintains the shutdown state, without outputting the working voltage, and the corresponding source driver circuit and gate driver circuit do not output signals, and the display panel normally turns off the screen, avoiding display anomalies or screen flashing.

[0057] When the supply voltage VCC completely drops to zero, the second comparator U2 stops working, and the second electronic switch Q2 and the third electronic switch Q3 have no startup voltage burned into the power management integrated circuit 200. Then, the power management integrated circuit 200 enables the initially set startup voltage Vth0 by default during the next power-on and realizes normal startup operation.

[0058] Among them, the first electronic switch Q1 and the second electronic switch Q2 can adopt NPN transistors or NMOS transistors based on their signal on-off modes, and the third electronic switch Q3 can adopt PNP transistors or PMOS transistors based on its signal on-off mode.

[0059] The size of the first capacitor C1 can be used to adjust the size of the second reference voltage Vref2, and the size of the second capacitor C2 can be used for the power-down detection time.

[0060] Embodiment 4 The present invention also proposes a display device, as Figure 5 shown. The display device includes a power management integrated circuit 200 and a voltage bounce compensation circuit 100. The specific structure of the voltage bounce compensation circuit 100 refers to the above embodiments. Since this display device adopts all the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one. Among them, the voltage bounce compensation circuit 100 is respectively connected to the power input terminal Vin and the startup voltage terminal Vth of the power management integrated circuit 200.

[0061] In this embodiment, the voltage bounce compensation circuit 100 compares and judges the supply voltage VCC during power-down, and switches to burn different sizes of startup voltages into the power management integrated circuit 200, so as to increase the set startup voltage of the power management integrated circuit 200 during the power-down process. When there is a voltage bounce, it prevents the power management integrated circuit 200 from restarting abnormally, thereby avoiding abnormal images or screen flashes on the display panel and improving the display effect.

[0062] The display device may further include a timing controller, a source driver circuit, a gate driver circuit, a display panel, etc. The power management integrated circuit 200 starts up and outputs a working voltage to the subsequent timing controller, source driver circuit, gate driver circuit, display panel, etc. The source driver circuit is used to output data signals under the control of the timing controller, and the gate driver circuit is used to output scan signals and scan the display panel row by row under the control of the timing controller. The display panel displays corresponding image information under the drive of the data signals and scan signals.

[0063] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A voltage bounce compensation circuit, characterized in that, Connected to the power management integrated circuit of the display device, the power input terminal of the power management integrated circuit is used to input a supply voltage, and the power management integrated circuit starts to work when the supply voltage is greater than the startup voltage burned in the startup voltage terminal or greater than the initial startup voltage. The voltage bounce compensation circuit includes: A state storage circuit, connected to the power input terminal of the power management integrated circuit, and the state storage circuit is used to charge when the power management integrated circuit is initially powered on and output a first terminal voltage; A power-down detection circuit, connected to the power input terminal of the power management integrated circuit and the state storage circuit respectively, and the power-down detection circuit is used to compare the supply voltage with a first reference voltage, and discharge the first terminal voltage when the supply voltage is less than the first reference voltage; A startup voltage output circuit, connected to the power input terminal of the power management integrated circuit, the startup voltage terminal and the state storage circuit respectively, and the startup voltage output circuit is used to compare the first terminal voltage with a second reference voltage; When the first terminal voltage is greater than the second reference voltage, burn a first startup voltage to the startup voltage terminal of the power management integrated circuit, and when the first terminal voltage is less than or equal to the second reference voltage, burn a second startup voltage to the startup voltage terminal of the power management integrated circuit. The first startup voltage is greater than the second startup voltage, and the second startup voltage is greater than the initial startup voltage; And cut off the output of the corresponding startup voltage when there is no supply voltage input to the power management integrated circuit.

2. The voltage bounce compensation circuit according to claim 1, characterized in that, The state storage circuit includes a first diode and a first capacitor; The anode of the first diode is connected to the power input terminal of the power management integrated circuit, and the cathode of the first diode and the first end of the first capacitor are connected to form the power output terminal of the state storage circuit, and the second end of the first capacitor is grounded.

3. The voltage bounce compensation circuit according to claim 1, wherein The power-down detection circuit includes: A power supply circuit, connected to the power input terminal of the power management integrated circuit, and the power supply circuit is used to charge when the power management integrated circuit is initially powered on and output a second terminal voltage; A first comparison circuit, connected to the power input terminal of the power management integrated circuit and the power supply circuit respectively, for comparing the supply voltage with the first reference voltage, and outputting a first switch signal when the supply voltage is greater than the first reference voltage, and outputting a second switch signal when the supply voltage is less than or equal to the first reference voltage; A discharge circuit, connected between the state storage circuit and the ground, and the discharge circuit is also connected to the first comparison circuit. The discharge circuit is triggered by the first switch signal to turn off, and is triggered by the second switch signal to turn on and discharge the first terminal voltage.

4. The voltage bounce compensation circuit according to claim 3, wherein The power supply circuit includes a second diode and a second capacitor; The anode of the second diode is connected to the power input terminal of the power management integrated circuit, and the cathode of the second diode and the first end of the second capacitor form the output terminal of the power supply circuit, and the second end of the second capacitor is grounded.

5. The voltage bounce compensation circuit according to claim 3, wherein, The first comparison circuit includes a first voltage stabilizing diode and a first comparator; The inverting input terminal of the first comparator is connected to the power input terminal of the power management integrated circuit. The cathode of the first voltage stabilizing diode, the non-inverting input terminal of the first comparator, and the power input terminal of the power management integrated circuit are connected. The anode of the first voltage stabilizing diode is grounded. The power supply terminal of the first comparator is connected to the power output terminal of the power supply circuit. The output terminal of the first comparator constitutes the output terminal of the first comparison circuit.

6. The voltage bounce compensation circuit according to claim 3, wherein The discharging circuit includes a first resistor and a first electronic switch tube; The first end of the first resistor is connected to the output terminal of the first comparison circuit. The second end of the first resistor is connected to the control terminal of the first electronic switch tube. The first end of the first electronic switch tube is grounded. The second end of the first electronic switch tube is connected to the power output terminal of the state storage circuit.

7. The voltage bounce compensation circuit according to any one of claims 1 to 6, characterized in that, The startup voltage output circuit includes: A second comparison circuit, which is respectively connected to the power input terminal of the power management integrated circuit and the state storage circuit. The second comparison circuit is used to compare the first terminal voltage with a second reference voltage, output a first switching signal when the first terminal voltage is greater than the second reference voltage, output a second switching signal when the first terminal voltage is less than or equal to the second reference voltage, and cut off the output of the corresponding switching signal when there is no power supply voltage input to the power management integrated circuit; A voltage switching output circuit, which is respectively connected to the second comparison circuit and the startup voltage terminal of the power management integrated circuit. The voltage switching output circuit is used to switch and output the first startup voltage when receiving the first switching signal, and switch and output the second startup voltage when receiving the second switching signal.

8. The voltage bounce compensation circuit according to claim 7, characterized in that, The second comparison circuit includes a second resistor, a second voltage stabilizing diode and a second comparator; The first end of the second resistor is connected to the power output terminal of the state storage circuit. The second end of the second resistor is connected to the non-inverting input terminal of the second comparator. The cathode of the second voltage stabilizing diode, the power input terminal of the power management integrated circuit, and the inverting input terminal of the second comparator are connected. The anode of the second voltage stabilizing diode is grounded. The power supply terminal of the second comparator is connected to the power input terminal of the power management integrated circuit. The output terminal of the second comparator constitutes the signal output terminal of the second comparison circuit.

9. The voltage bounce compensation circuit according to claim 7, wherein The voltage switching output circuit includes a third resistor, a second electronic switch tube and a third electronic switch tube; The first end of the third resistor is connected to the signal output terminal of the second comparison circuit. The second end of the third resistor, the control terminal of the second electronic switch tube, and the control terminal of the third electronic switch tube are connected. The first end of the second electronic switch tube is used to input the first startup voltage. The first end of the third electronic switch tube is used to input the second startup voltage. The second ends of the second electronic switch tube and the third electronic switch tube are connected to constitute the power output terminal of the voltage switching output circuit.

10. A display device, characterized in that, Comprising a power management integrated circuit and a voltage bounce compensation circuit as described in any one of claims 1 to 9, the voltage bounce compensation circuit is respectively connected to the power input terminal and the startup voltage terminal of the power management integrated circuit.

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