CN102684163B - Full load self-detection protection module for charge pump - Google Patents

Abstract

The invention discloses a full load self-detection protection module for a charge pump. The full load self-test protection module is characterized by comprising a power supply comparison module, a startup charging current-limiting unit, a hysteresis comparison unit, a load detection unit, a first comparator CMP1, a second comparator CMP2, a third comparator CMP3, a fourth comparator CMP4, a comparator control unit and a controlled protection starting unit. According to the invention, the full load self-detection protection module is applicable to a circuit, so the circuit can operate under any loading condition accurately and safely, the safety of the whole chip is ensured, and the working efficiency of the chip is greatly improved.

Description

A kind of full load is from detecting charge pump protection module

Technical field

The present invention be the reliability in order to improve charge pump switches power supply and design possess full load from detect protection module, belong to field of switch power.

Background technology

Along with a large amount of of consumer electronics product popularize, especially become electronic product main flow direction with apple panel computer for representing miniaturization, intellectuality, and the power pack of electronic product is in order to raise the efficiency, tend to select inductance type Switching Power Supply, and inductance in Switching Power Supply is because its larger volume, under some occasion, restricted again its application, and the existence of large capacity ceramic paster electric capacity becomes more and more popular switched capacitance charge pump circuit; Meanwhile the relevant reliability of switching capacity, EMC have also been proposed to more and more higher requirement, the theory that is applicable in a large number inductance type in the past is no longer applicable to capacitance charge pump circuit.

The design is mainly the protection module for switched capacitance charge pump circuit design; this module adopts full load automatically to detect protection, the startup stage of according to difference, different power voltage, different loads, this circuit design corresponding protection module; ensure that circuit working is in safety, low EMC state.

Summary of the invention

The present invention seeks to design one possess full load from detect protection module be applied in switched capacitance charge pump circuit.

The present invention for achieving the above object, adopts following technical scheme:

A kind of full load, from detecting charge pump protection module, is characterized in that: it comprises power supply comparison module, start charging current limiter unit, hysteresis comparing unit, load detecting unit, the first comparator C MP1, the second comparator C MP2, the 3rd comparator C MP3, the 4th comparator C MP4, comparator control unit, controlled protection start unit;

The effect of described power supply comparison module: in when start owing to being output as electronegative potential, the switching tube power supply of charge pump is power supply, in the time that output exceedes power supply, switch to the output pin of charge pump by power supply comparison module to the switching tube power supply of charge pump, realize power-on protection in conjunction with start charging current limiter unit;

Described hysteresis comparing unit is used for preventing the interference of power supply noise;

Described start charging current limiter unit, for limiting the bias current of output power supply, prevents from, because output connects heavy duty or short circuit startup, causing the high-power loss of efferent duct or burning efferent duct;

Different comparators, for detection of load resistance, according to different load resistances, is opened in described load detecting unit;

Described the first comparator C MP1, the second comparator C MP2, the 3rd comparator C MP3, the 4th comparator C MP4 input by described load detecting unit controls; The first comparator C MP1 unlocking condition is that load is greater than 1k Ω, comprises zero load; The unlocking condition of the second comparator C MP2 is: load 50 Ω are between 1k Ω; The unlocking condition of the 3rd comparator C MP3 is that load is less than 50 Ω and comprises output short-circuit; The unlocking condition of the 4th comparator C MP4 is that output connects the power supply higher than 5V; Each comparator output access comparator control unit;

Described comparator control unit comprises three and door and oscillator, three and door are controlled respectively in the first comparator C MP1, the second comparator C MP2, the 3rd comparator C MP3 output, any one comparator is that comparator is output as zero after opening, and exporting with door is all also zero; The 4th comparator C MP4 directly controls the switch of oscillator; The output of oscillator accesses three and door of comparator control unit simultaneously;

Described controlled protection start unit comprises charge pump switches pipe, and described charge pump switches pipe is by the control of comparator control unit; Directly control charge pump switches pipe with the output of door for three, be output as at 1 o'clock with door, charge pump switches pipe is in closed condition, and electric charge cannot transmit, and charge pump relies on output capacitance power supply, the current drain state that chip operation is extremely low; The 4th comparator C MP4 is output as at 1 o'clock, and directly, the oscillator of comparator control unit and controlled protection start unit charge pump switches pipe Close All, circuit is in holding state;

The 3rd comparator C MP3 exports also for controlling the drive current of charge pump switches pipe, drive current is limited under specific starting current, bootrom, in the time that the 3rd comparator C MP3 starts, output is limited in very low output level by heavy duty, now the drive current of this comparator restriction driving tube, maintains under a constant state drive current, has limited the loss of circuit.

The present invention is owing to having adopted full load to be applied in circuit from detecting protection module, circuit can be accurately safety be operated in any loading condition, ensured whole chip safety, greatly improved the operating efficiency of chip.

Brief description of the drawings

Fig. 1 is full load protective circuit part-structure block diagram of the present invention;

Fig. 2 is comparator control unit and controlled protection module structured flowchart.

Embodiment

One possesses full load and comprises from detecting protection module as shown in Figure 1: power supply comparison module, start charging current limiter unit, hysteresis comparing unit, load detecting unit, the first comparator C MP1, the second comparator C MP2, the 3rd comparator C MP3, the 4th comparator C MP4, comparator control unit, controlled protection start unit.

While just powering on, supply voltage is set up, and charge pump power supply is output as charged state, by power supply comparison module, determines the power supply of rear pump mains switch part, and hysteresis comparing unit is used for preventing the interference of power supply noise; The bias current of the output power supply charging current limiter unit of being started shooting limits, and prevents from connecing heavy duty or short circuit starts because of output, causes the high-power loss of efferent duct, causes and burns efferent duct, and now inner OSC is in closed condition, and pumping source module is also not activated; Export basicly stable after, chip by load detecting unit inspection load resistance, according to different load resistances, is opened different comparators.

Comparator control unit comprise three with door and oscillator, the first comparator C MP1, the second comparator C MP2, the 3rd comparator C MP3 output control respectively three with door, any one comparator is that comparator is output as zero after opening, with door output be all also zero.The 4th comparator C MP4 directly controls the switch of oscillator; The output of oscillator accesses three and door of comparator control unit simultaneously.

The main unlocking condition of the first comparator C MP1 is: be greater than the load (comprising zero load) of 1k Ω; Now chip OSC starts, but charge pump switches pipe within the time of 99% left and right in closed condition, almost nil to outside EMC and FM Band Interference, the time of closing mainly determines by the hysteresis voltage amplitude of the first comparator C MP1 and the size of outside output loading and decoupling capacitance.

The unlocking condition of the second comparator C MP2 is: 50 Ω are to the load between 1k Ω, it is now normal operating load, this comparator most of the time, in closed condition, can not go to close charge pump efferent duct, because charge pump charging current is now slightly larger than load discharge electric current, output voltage rising, in the time comparison point being set higher than inside, comparator is opened, and closes efferent duct, by output capacitance power supply, lower than set comparison point time, charge pump is powered again.The feature of this comparator is exactly to ensure in the situation that meeting normal power supply, in part-time, realizes and closes charge pump.To a certain degree improve the efficiency of chip, reduced the power consumption of chip.

The 3rd comparator C MP3 unlocking condition: load is less than 50 Ω; the 3rd comparator C MP3 exports also for controlling the drive current of charge pump switches pipe; the size of chip detection efferent duct electric current arranges electric current with protection point and compares; be greater than after setting; directly close vibration; and frequency counter zero clearing, efferent duct drive current is automatically made constant 300mA. and prevents from, because of efferent duct short circuit, burning efferent duct.

The 4th comparator C MP4 unlocking condition: when circuit output connects active device, circuit start OSC efferent duct all turn-offs, and is high-impedance state.Thoroughly protection efferent duct.

Claims (1)

1. full load, from detecting a charge pump protection module, is characterized in that: it comprises power supply comparison module, start charging current limiter unit, hysteresis comparing unit, load detecting unit, the first comparator C MP1, the second comparator C MP2, the 3rd comparator C MP3, the 4th comparator C MP4, comparator control unit, controlled protection start unit;

The effect of described power supply comparison module: in when start owing to being output as electronegative potential, the switching tube power supply of charge pump is power supply, in the time that output exceedes power supply, switch to the output pin of charge pump by power supply comparison module to the switching tube power supply of charge pump, realize power-on protection in conjunction with start charging current limiter unit;

Described hysteresis comparing unit is used for preventing the interference of power supply noise;

Described start charging current limiter unit, for limiting the bias current of output power supply, prevents from, because output connects heavy duty or short circuit startup, causing the high-power loss of efferent duct or burning efferent duct;

Different comparators, for detection of load resistance, according to different load resistances, is opened in described load detecting unit;

Described the first comparator C MP1, the second comparator C MP2, the 3rd comparator C MP3, the 4th comparator C MP4 input by described load detecting unit controls; The first comparator C MP1 unlocking condition is that load is greater than 1k Ω, comprises zero load; The unlocking condition of the second comparator C MP2 is: load 50 Ω are between 1k Ω; The unlocking condition of the 3rd comparator C MP3 is that load is less than 50 Ω and comprises output short-circuit; The unlocking condition of the 4th comparator C MP4 is that output connects the power supply higher than 5V; Each comparator output access comparator control unit;

Described comparator control unit comprises three and door and oscillator, three and door are controlled respectively in the first comparator C MP1, the second comparator C MP2, the 3rd comparator C MP3 output, any one comparator is that comparator is output as zero after opening, and exporting with door is all also zero; The 4th comparator C MP4 directly controls the switch of oscillator; The output of oscillator accesses three and door of comparator control unit simultaneously;

Described controlled protection start unit comprises charge pump switches pipe, and described charge pump switches pipe is by the control of comparator control unit; Directly control charge pump switches pipe with the output of door for three, be output as at 1 o'clock with door, charge pump switches pipe is in closed condition, and electric charge cannot transmit, and charge pump relies on output capacitance power supply, the current drain state that chip operation is extremely low; The 4th comparator C MP4 is output as at 1 o'clock, and directly, the charge pump switches pipe Close All of the oscillator of comparator control unit and controlled protection start unit, circuit is in holding state;

The 3rd comparator C MP3 exports also for controlling the drive current of charge pump switches pipe, drive current is limited under specific starting current, bootrom, in the time that the 3rd comparator C MP3 starts, output is limited in very low output level by heavy duty, now the drive current of this comparator restriction driving tube, maintains under a constant state drive current, has limited the loss of circuit.