CN207896665U

CN207896665U - Meet storage battery power supply voltage instability and protects the protective device of LCD screen

Info

Publication number: CN207896665U
Application number: CN201720548240.4U
Authority: CN
Inventors: 林祖武; 常云锋
Original assignee: Jinpin Electrical Co Ltd Zhuhai SEZ
Current assignee: Jinpin Electrical Co Ltd Zhuhai SEZ
Priority date: 2017-05-17
Filing date: 2017-05-17
Publication date: 2018-09-21
Anticipated expiration: 2027-05-17

Abstract

The utility model provides the utility model and provides a kind of protective device for meeting storage battery power supply voltage instability and protecting LCD screen; it includes that sequentially connected supply input interface, the circuit of resistance to reversal connection, ON-OFF control circuit and power supply output interface, the ON-OFF control circuit are controlled by high-low voltage detection circuit output signal.In the case where not increasing too many cost, this programme can reduce due to merely using diode as anti-reverse measure and caused by voltage decline, reduce diode on because directly by high current caused by Wen Sheng, protect circuit main board and shield be not burned.

Description

Meet storage battery power supply voltage instability and protects the protective device of LCD screen

Technical field

The utility model belongs to LCD TV field more particularly to a kind of voltage instability of storage battery power supply LCD TV is protected Protection unit.

Background technology

In the prior art, when television set is powered using accumulator (storage battery), user is reversed positive and negative anodes in order to prevent And circuit main board is burnt out, a kind of simple, reliable and at low cost method can be used, anti-reverse two are exactly concatenated in power supply circuit Pole pipe is just unlikely to burn out mainboard and causes damages in this way when user is reversed.But major limitation existing for this design, It is exactly that can not play the role of high pressure or low-voltage variation when battery tension is unstable, this will cause because of overtension or too low When be possible to that mainboard or display screen can be burnt out.Moreover, under this approach, since diode has the pressure drop of 0.3-0.4V or so, Screen TCON power supplies can be caused to decline, it is possible to cause certain probabilistic display abnormal.

Invention content

The utility model provides a kind of protective device for meeting storage battery power supply voltage instability and protecting LCD screen, purport Solving the problems, such as background technology.The technical solution adopted in the utility model is：

Meet storage battery power supply voltage instability and protects the protective device of LCD screen, including sequentially connected supply input Interface, the circuit of resistance to reversal connection, ON-OFF control circuit and power supply output interface；The ON-OFF control circuit is by metal-oxide-semiconductor (QM5), three poles Manage (QM9), two divider resistances (R6, R7), the capacitance (C86) being connected between metal-oxide-semiconductor (QM5) grid source electrode, power filtering capacitor (C15) and it is connected to current-limiting resistance (R13) composition of triode (QM9) base stage, the grid of the metal-oxide-semiconductor (QM5) is limited through another Leakage resistance (R25) is connected between two divider resistances (R6, R7)；The ON-OFF control circuit is by high-low voltage detection circuit Output signal controls.

The protective device for meeting storage battery power supply voltage instability and protecting LCD screen, it is characterised in that：It is described The circuit of resistance to reversal connection by metal-oxide-semiconductor (QM1), the capacitance (C1) being connected between the metal-oxide-semiconductor grid source electrode, two divider resistances (R1, R2), two anti-reverse diode (D2, D3) compositions for being connected to the metal-oxide-semiconductor, the grid of the metal-oxide-semiconductor are connected to described two Between divider resistance (R1, R2).

The protective device for meeting storage battery power supply voltage instability and protecting LCD screen, it is characterised in that：It is described High-low voltage detection circuit includes high-voltage detecting circuit and low-voltage testing circuit, and operating voltage is provided by comparator power supply circuit, The high-voltage detecting circuit includes comparator (U19A), and power supply is followed by through divider filter in the comparator (U19A) reverse side, The reference voltage caused by the reference voltage generating circuit is connected to its positive terminal, and the output end of the comparator (U19A) is through aforementioned limit Leakage resistance (R13) is connected to triode (QM9) base stage；The low-voltage testing circuit includes another comparator (U19B), and power supply is through dividing Press filtration wave is followed by the comparator (U19B) positive terminal, and the reference voltage caused by the reference voltage generating circuit is connected to its reverse phase End is connected to feedback resistance (R5) between the output end and positive terminal of the comparator (U19B), and output end is through aforementioned current limliting electricity Resistance (R13) is connected to triode (QM9) base stage.

The protective device for meeting storage battery power supply voltage instability and protecting LCD screen, it is characterised in that：It is described Reference voltage generating circuit includes that two divider resistances (R78, R4) and the voltage stabilizing being in parallel with one of resistance (R4) integrate Circuit (U21) and filter capacitor (C98) provide benchmark electricity after current-limiting resistance (R83) for aforementioned comparator (U19A, U19B) Pressure；The comparator power supply circuit after two resistance (R24, R28) parallel connections by connecting another voltage-stabiliser tube (D1), and voltage is by this One end of voltage-stabiliser tube (D1) exports.

The protective device for meeting storage battery power supply voltage instability and protecting LCD screen, it is characterised in that：It is described Reference voltage be set as 1.25 volts, the comparator operating voltage be set as 5.1 volts；The high-voltage detecting circuit detection voltage is set It is set to 14.2 volts, the low-voltage testing circuit detection voltage is set as 11.1 volts.

The utility model is beneficial in that, in the case where not increasing too many cost, can be solved three simultaneously and be asked Topic：1, reduce due to merely using diode as anti-reverse measure and caused by voltage decline；2, it reduces on diode because straight Wen Sheng caused by connecting super-high-current；3, high-low voltage safeguard measure is increased, to protect circuit main board and screen to be unlikely to burn It is bad.

Description of the drawings

Fig. 1 is the principles of the present invention block diagram；

Fig. 2 is the input interface of the utility model and the circuit of resistance to reversal connection；

Fig. 3 is the ON-OFF control circuit of the utility model.

Fig. 4 is the reference voltage generating circuit of the utility model

Fig. 5 is the comparator power supply circuit of the utility model

Fig. 6 is the comparator input of the utility model higher than 14.2V detection protection circuits

Fig. 7 is the comparator input of the utility model less than 11.1V detection protection circuits

Specific implementation mode

One embodiment of the utility model is described further below in conjunction with the accompanying drawings.

As shown in Figure 1, the operation principle of the utility model is, external dc is powered after " supply input interface ", first " circuit of resistance to reversal connection " is first passed through, reverse connection of accumulator is prevented and the pressure drop on anti-reverse diode can be reduced, and can be by big Electric current and diode will not overheat；Rear class ON-OFF control circuit is given by the DC voltage that " circuit of resistance to reversal connection " exports；It is described to open It closes control circuit to be controlled by high-low voltage detection circuit, the voltage between 11.1-14.2V can be made to pass through power supply output interface It exports to mainboard, and the voltage more than this range cannot be exported.

Fig. 2 show the input interface of utility model and the circuit of resistance to reversal connection.AV6 is LCD TV direct current supply interface, F1 For fuse in machine, it can fuse, shield under high current；QM1, C1, R1, R2, D2, D3 form the circuit of resistance to reversal connection.QM1 Using PMOS tube, when inputting forward voltage, grid is in low potential, and hourglass source electrode is opened, and when electric current passes through QM1 the characteristics of is Generated pressure drop is low, loss is low, can pass through high current；When voltage is reversed, can effectively end.

Fig. 3 show the ON-OFF control circuit of the utility model.The ON-OFF control circuit of the utility model by R13, R6, R7, R25, C86, QM5, QM9, C15 are formed, and QM5 uses PMOS tube, QM9 that NPN triode, QM9 base stages is used to connect high-low voltage inspection The output end of slowdown monitoring circuit.When the output voltage of high-low voltage detection circuit is high level, the base stage of QM9 is high level, C/E Pole is connected, and to which QM5 hourglass source electrodes are opened, voltage is exported by output interface of powering to mainboard；When high-low voltage detection circuit When output voltage is low level, the base stage of QM9 is low level, the cut-off of the poles C/E, QM5 hourglass source electrodes cut-off, to output voltage Cut-off.

Fig. 4 is the reference voltage generating circuit of the utility model, and Fig. 5 is the comparator power supply circuit of the utility model. R78, U21, C98, R4, R83 form ultralow pressure reference voltage-stabilizing circuit, and wherein U21 is adjustable steady using three end of low pressure of BCD companies It is 1.25 volts to press integrated circuit AZ432ARTR-E1, output voltage CMP1V25.R24, R28, D1 are comparator power supply circuit, Output voltage PD5V is 5.1 volts.

U19A, U19B and its peripheral circuit composition high-low voltage protect detection circuit.Fig. 6 is the comparator of the utility model Circuit is protected in higher than 14.2 volts detections of input.R79, R860, R86, C99, R75, C16, C103, R35, U19A form high pressure 14.2 volts of detection circuits, wherein U19A use LM393ADR comparators, 5.1 volts of voltages of comparator power supply circuit output filtered 8 feet of LM393ADR are accessed afterwards, and input voltage accesses the reverse side 2 of U19A, ultralow pressure reference voltage-stabilizing circuit after divider filter 3,4 foot of the positive terminal ground connection of 1.25 volts of reference voltages access U19A of output.When input voltage be higher than 14.2 volts when, due to than It is less than negative terminal voltage compared with the positive terminal voltage of device, comparator U19A exports low level PDONOFF, and to control QM5, QM9 cut-off, shutdown is defeated Go out voltage, to protect the safety of late-class circuit.

Fig. 7 is that circuit is protected in less than 11.1 volts detections of comparator input of the utility model.R43、R500、 R50、C17、 R51, R5, U19B form 11.1 volts of detection circuits of low pressure, and wherein U19B uses LM393ADR comparators, comparator power supply circuit 8 feet of the filtered rear access LM393ADR of 5.1 volts of voltages of output, input voltage access the positive terminal of U19A after divider filter 5,6,4 foot of the reverse side ground connection of 1.25 volts of reference voltages access U19B of ultralow pressure reference voltage-stabilizing circuit output.When input electricity It forces down when 11.1 volts, since comparator anode is less than negative terminal voltage, comparator U19B exports low level PDONOFF, to control QM5, QM9 end, and turn off output voltage, achieve the purpose that protect late-class circuit.

Claims

1. meeting storage battery power supply voltage instability and protecting the protective device of LCD screen, it is characterised in that：Including being sequentially connected Supply input interface, the circuit of resistance to reversal connection, ON-OFF control circuit and power supply output interface；The ON-OFF control circuit is by metal-oxide-semiconductor (QM5), triode (QM9), two divider resistances (R6, R7), the capacitance (C86) being connected between metal-oxide-semiconductor (QM5) grid source electrode, power supply Filter capacitor (C15) and current-limiting resistance (R13) composition for being connected to triode (QM9) base stage, the grid warp of the metal-oxide-semiconductor (QM5) Another current-limiting resistance (R25) is connected between two divider resistances (R6, R7)；The ON-OFF control circuit is by high-low voltage Detection circuit output signal controls.

2. the protective device as described in claim 1 for meeting storage battery power supply voltage instability and protecting LCD screen, feature It is：The circuit of resistance to reversal connection is by metal-oxide-semiconductor (QM1), the capacitance (C1) being connected between the metal-oxide-semiconductor grid source electrode, two partial pressures Resistance (R1, R2), two anti-reverse diode (D2, D3) compositions for being connected to the metal-oxide-semiconductor, the grid of the metal-oxide-semiconductor are connected to Between two divider resistances (R1, R2).

3. meeting storage battery power supply voltage instability and protecting LCD screen as described in any claim in claims 1 or 2 Protective device, it is characterised in that：The high-low voltage detection circuit includes high-voltage detecting circuit and low-voltage testing circuit, by than Operating voltage is provided compared with device power supply circuit, the high-voltage detecting circuit includes comparator (U19A), and power supply is followed by through divider filter In the comparator (U19A) reverse side, the reference voltage caused by the reference voltage generating circuit is connected to its positive terminal, the ratio Output end compared with device (U19A) is connected to triode (QM9) base stage through aforementioned current-limiting resistance (R13)；The low-voltage testing circuit includes Another comparator (U19B), power supply are followed by through divider filter in the comparator (U19B) positive terminal, from reference voltage generating circuit Generated reference voltage is connected to its reverse side, and feedback resistance is connected between the output end and positive terminal of the comparator (U19B) (R5), output end is connected to triode (QM9) base stage through aforementioned current-limiting resistance (R13).

4. the protective device as claimed in claim 3 for meeting storage battery power supply voltage instability and protecting LCD screen, feature It is：The reference voltage generating circuit includes two divider resistances (R78, R4) and is in parallel with one of resistance (R4) Integrated regulator (U21) and filter capacitor (C98) provide after current-limiting resistance (R83) for aforementioned comparator (U19A, U19B) Reference voltage；The comparator power supply circuit after two resistance (R24, R28) parallel connections by connecting another voltage-stabiliser tube (D1), voltage It is exported by one end of the voltage-stabiliser tube (D1).

5. the protective device as claimed in claim 4 for meeting storage battery power supply voltage instability and protecting LCD screen, feature It is：The reference voltage be set as 1.25 volts, the comparator operating voltage be set as 5.1 volts；The high-voltage detecting circuit Detection voltage is set as 14.2 volts, and the low-voltage testing circuit detection voltage is set as 11.1 volts.