CN211554776U - Reference current generating circuit with starting circuit - Google Patents

Abstract

The utility model discloses a take starting circuit's reference current to produce circuit, be applied to LED display screen driver chip reference circuit's starting circuit, it includes interconnect's reference circuit and starting circuit, reference circuit includes PMOS pipe one, PMOS pipe two, PMOS pipe three and NMOS pipe one, starting circuit includes PMOS pipe four, PMOS pipe five, phase inverter one, resistance four and Schmidt trigger, PMOS pipe four and PMOS pipe five source electrode connect the source electrode of PMOS pipe three and be connected with the power end, PMOS pipe four grid connection PMOS pipe three grid, PMOS pipe four drain electrode connection phase inverter one's input and resistance four one end, resistance four other end connection earthing terminal, Schmidt trigger's input is connected to phase inverter one's output, PMOS pipe five grid is connected to Schmidt trigger's output, PMOS pipe five grid is connected to PMOS pipe five drain electrode connection NMOS pipe one's grid; the utility model discloses an among the starting circuit drive circuit contain the Schmidt trigger, do not have the intermediate state, improved reference circuit's stability and interference killing feature.

Description

Reference current generating circuit with starting circuit

Technical Field

The utility model relates to a starting circuit of LED display screen driver chip reference circuit specifically relates to a take starting circuit's reference current to produce circuit.

Background

Fig. 1 is a conventional start-up circuit and reference circuit.

The LED panel driving chip reference circuit has a plurality of stable states, for example, when V1 is VX, VY, and PM1, PM2, PM3, and NM1 are all turned off, and the reference circuit is also stable, but cannot generate the required reference current, so a start-up circuit is required to enable the reference circuit to operate normally.

In fig. 1, PM1, PM2, PM3, and PM4 form a current mirror, when the current flowing through PM1, PM2, and PM3 is small or 0, the current of PM4 is also small or 0, voltage V0 at the drain terminal of PM4 is pulled down very low by R4, V0 controls PM5 to open after passing through inverters INV1 and INV2, a strong pull-up is formed for gate terminal voltage V1 of NM1, V1 gradually increases, when V1 is greater than threshold voltage VTH of NM1, NM1 turns on and pulls down the potential of V1, PM1, and PM1 are turned on, the reference circuit starts up, when the current flowing through PM1, PM1 gradually increases to raise voltage V1, when the current flowing through PM1, PM 4672, PM1 turns off to a certain degree, PM1 turns over the gate voltage V1, PM1 turns over the normal gate voltage 1, PM1 turns over the level turns off.

Since the inverter operates in the intermediate state with a certain probability, namely the input and output voltages of the inverter are both at the intermediate potential between VDD and GND, and the PM5 is driven by the inverter, during the starting process, the starting circuit is stabilized in the intermediate state with a certain probability along with the increase of the voltage of V0, and the PM5 has a weak pull-up on the potential of V1, so that the reference circuit operates abnormally.

Therefore, how to solve the above technical problems becomes an urgent problem to be solved.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is not enough to the above-mentioned of prior art, the utility model provides a take starting circuit's reference current to produce the circuit, include schmitt trigger among its PMOS pipe drive circuit that corresponds, schmitt trigger's characteristics lie in only two stable state, to the input signal that negatively degressive and two kinds of different directions of change are progressively increased progressively with the positive direction, schmitt trigger has different threshold voltage, only when input voltage takes place enough the change, the output just can change, output voltage is VDD or GND, therefore, in the starting process, the PMOS pipe that corresponds only can be in strong pull-up state or turn-off state, no intermediate state, reference circuit's stability has been improved.

In order to solve the technical problem, the utility model discloses a take starting circuit's reference current to produce circuit, including interconnect's reference circuit and starting circuit, the reference circuit includes PMOS pipe one, PMOS pipe two and PMOS pipe three that the source electrode is connected together, and mains voltage inputs the source electrode of three PMOS pipes, and the grid of three PMOS pipes is connected together; the drain electrode of the PMOS tube I is respectively connected with one ends of a resistor I and a resistor II, the other end of the resistor I is connected with the emitting electrode of the zero PNP type triode, and the base electrode and the collector electrode of the zero PNP type triode are connected with the other end of the resistor II to be connected with the grounding end; the drain electrode of PMOS pipe two is connected with the projecting pole of a PNP type triode and the one end of resistance three respectively, the base of a PNP type triode, the other end of collecting electrode and resistance three is connected together and is connected with the earthing terminal, the anodal PMOS pipe drain electrode of connecting of the input of amplifier, the drain electrode of PMOS pipe one is connected to amplifier input negative pole, the grid of NMOS pipe one is connected to the output of amplifier, the grid of PMOS pipe three links together and is connected with the drain electrode of NMOS pipe one with the drain electrode, the earthing terminal is connected to the source electrode of NMOS pipe, its characterized in that: the starting circuit comprises a PMOS tube four, a PMOS tube five, a phase inverter one, a resistor four and a Schmidt trigger, wherein the source electrodes of the PMOS tube four and the PMOS tube five are connected with the source electrode of the PMOS tube three and are connected with a power supply end, the grid electrode of the PMOS tube four is connected with the grid electrode of the PMOS tube three, the drain electrode of the PMOS tube four is connected with the input end of the phase inverter one and one end of the resistor four, the other end of the resistor four is connected with a grounding end, the output end of the phase inverter one is connected with the input end of the Schmidt trigger, the output end of the Schmidt trigger is connected with the grid electrode of the PMOS tube five, and the drain electrode.

Further enabling the inverter one in the circuit and the Schmitt trigger to be interchanged in position.

The utility model discloses an after the above-mentioned circuit structure, contain schmitt trigger SCHMITTTRIGGER in the starting circuit, schmitt trigger's characteristics lie in only two stable state, to the input signal that negatively degressive and two kinds of different directions of change are progressively increased progressively with positive, schmitt trigger has different threshold voltage, only when input voltage takes place enough changes, just can change in the output, output voltage is VDD or GND. Therefore, during the starting process, the PM5 is only in a strong pull-up state or a turn-off state, and has no intermediate state, so that the stability of the reference circuit is improved; in addition, the positions of the Schmitt trigger and the inverter in the starting circuit can be interchanged, so that the flexibility of the circuit structure is improved.

Drawings

FIG. 1 is a start-up circuit and a reference circuit commonly used in the prior art;

fig. 2 is a reference current generating circuit with a start circuit according to the present invention.

Detailed Description

The invention will be described in further detail with reference to examples of embodiments shown in the drawings, which are not intended to limit the invention in any way.

As shown in fig. 2, the reference current generating circuit with starting circuit of the present invention comprises a reference circuit and a starting circuit which are connected with each other, wherein the reference circuit comprises a first PMOS transistor, a second PMOS transistor and a third PMOS transistor, the source electrodes of the first PMOS transistor, the second PMOS transistor and the third PMOS transistor are connected together, the power voltage is inputted into the source electrodes of the three PMOS transistors, and the grid electrodes of the three PMOS transistors are connected together; the drain electrode of the PMOS tube I is respectively connected with one ends of a resistor I and a resistor II, the other end of the resistor I is connected with the emitting electrode of the zero PNP type triode, and the base electrode and the collector electrode of the zero PNP type triode are connected with the other end of the resistor II to be connected with the grounding end; the drain electrode of the PMOS tube II is respectively connected with the emitter electrode of the PNP type triode I and one end of the resistor III, the base electrode, the collector electrode and the other end of the resistor III of the PNP type triode I are connected with the grounding terminal, the positive electrode of the input end of the amplifier is connected with the drain electrode of the PMOS tube II, the negative electrode of the input end of the amplifier is connected with the drain electrode of the PMOS tube I, the output end of the amplifier is connected with the grid electrode of the NMOS tube I, the grid electrode of the PMOS tube III is connected with the grounding terminal, the source electrode of the NMOS tube is connected with the grounding terminal, the starting circuit comprises a PMOS tube IV, a PMOS tube V, a phase inverter I, a resistor IV and a Schmidt trigger, the source electrodes of the PMOS tube IV and the PMOS tube V are connected with the source electrode of the PMOS tube III and the power supply terminal, the grid electrode of the PMOS tube IV is connected with the grid electrode of the PMOS tube III, the output end of the first phase inverter is connected with the input end of the Schmitt trigger, the output end of the Schmitt trigger is connected with the grid electrode of the fifth PMOS tube, and the drain electrode of the fifth PMOS tube is connected with the grid electrode of the first NMOS tube.

Another embodiment of the present invention is to interchange the positions of the first inverter and the schmitt trigger in the starting circuit of fig. 2.

The utility model discloses when specifically using, because the characteristics of Schmidt trigger lie in only two stable state, to the input signal that negatively degressive and two kinds of different change directions of positive increment, Schmidt trigger has different threshold voltage, only when input voltage takes place enough changes, just can change in the output, output voltage is VDD or GND. Therefore, during start-up, PM5 in fig. 2 will only be in a strong pull-up state or an off state, with no intermediate state, improving the stability of the reference circuit.

In summary, the practical samples of the present invention have been prepared according to the description and the drawings, and the practical test results show that the utility model can achieve the expected purpose, and the practical value is undoubted. The above-mentioned embodiments are only used to conveniently illustrate the present invention, and are not to the limit of the present invention in any form, and any person who knows commonly in the technical field has, if not in the scope of the technical features of the present invention, utilize the present invention to make the equivalent embodiment of local change or modification, and not to break away from the technical features of the present invention, and all still belong to the technical features of the present invention.

Claims (2)

1. A reference current generating circuit with a starting circuit comprises a reference circuit and a starting circuit which are connected with each other, wherein the reference circuit comprises a first PMOS (P-channel metal oxide semiconductor) tube, a second PMOS tube and a third PMOS tube, source electrodes of the first PMOS tube, the second PMOS tube and the third PMOS tube are connected together, power supply voltage is input into the source electrodes of the three PMOS tubes, and grid electrodes of the three PMOS tubes are connected together; the drain electrode of the PMOS tube I is respectively connected with one ends of a resistor I and a resistor II, the other end of the resistor I is connected with the emitting electrode of the zero PNP type triode, and the base electrode and the collector electrode of the zero PNP type triode are connected with the other end of the resistor II to be connected with the grounding end; the drain electrode of PMOS pipe two is connected with the projecting pole of a PNP type triode and the one end of resistance three respectively, the base of a PNP type triode, the other end of collecting electrode and resistance three is connected together and is connected with the earthing terminal, the anodal PMOS pipe drain electrode of connecting of the input of amplifier, the drain electrode of PMOS pipe one is connected to amplifier input negative pole, the grid of NMOS pipe one is connected to the output of amplifier, the grid of PMOS pipe three links together and is connected with the drain electrode of NMOS pipe one with the drain electrode, the earthing terminal is connected to the source electrode of NMOS pipe, its characterized in that: the starting circuit comprises a PMOS tube four, a PMOS tube five, a phase inverter one, a resistor four and a Schmidt trigger, wherein the source electrodes of the PMOS tube four and the PMOS tube five are connected with the source electrode of the PMOS tube three and are connected with a power supply end, the grid electrode of the PMOS tube four is connected with the grid electrode of the PMOS tube three, the drain electrode of the PMOS tube four is connected with the input end of the phase inverter one and one end of the resistor four, the other end of the resistor four is connected with a grounding end, the output end of the phase inverter one is connected with the input end of the Schmidt trigger, the output end of the Schmidt trigger is connected with the grid electrode of the PMOS tube five, and the drain electrode.

2. The reference current generating circuit with starting circuit as claimed in claim 1, wherein the first inverter and the schmitt trigger in the starting circuit are interchanged.

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