CN202395653U - Modified return difference type power management circuit - Google Patents

Abstract

The utility model relates to a modified return difference type power management circuit. An input power Uin performs voltage subdivision through a resistance R1, a resistance R2 and a resistance R3, and then is connected to the grid of a switch tube Q1 through the connection point A of the resistance R1 and the resistance R2; the drain of the switch tube Q1 is connected to the grid of a switch tube Q2 through a resistance 5, and leads the electricity from the connection point D of the resistance 2 and the resistance 3, and is connected to the drain of a switch tube Q2 and the starting end C of a PWM controller through a diode D1; the drain of the switch tube Q2 and the starting end C of the PWM controller are respectively connected to the positive electrode of the input power Uin through a starting resistance Ro and a pull-up resistor; and the source electrodes of the switch tube Q1 and the switch tube Q2 and the GND end of the PWM controller are respectively grounded.

Description

A kind of back difference mode electric power management circuit of improvement

Technical field

The utility model relates to a kind of back difference mode electric power management circuit of improvement.

Background technology

In the existing photo-voltaic power supply product; Usually energy storage devices such as external storage battery of employing system or photovoltaic cell are that power circuit in the system provides power supply, however battery tension because the increase of depth of discharge, terminal voltage can slowly descend; After stopping discharge, terminal voltage can slowly be gone up again; Equally, photovoltaic cell is because the variation of the exposure intensity of the sun causes system power supply circuit supply shakiness, and the repeatedly starting and stopping of power circuit will cause the impact aging of starting shooting repeatedly to mainboard, the power amplifier board of back level, has reduced the life-span of this electronic system.

As shown in Figure 1, Chinese patent 201010251205.9, the normal open switch of employing relay J 1 and resistance R 1 and the structure that connects; When input supply voltage raises; Switching tube Q1 conducting drives the actuating of relay, and resistance R 1 is by short circuit, and the grid dividing potential drop coefficient of switching tube Q1 diminishes; Make relay get the input power supply threshold voltage of electric input power supply threshold voltage greater than dead electricity, even back level power supply circuit powers on and the input power supply threshold voltage of power down between produce return difference.This structure has effectively been avoided the system works swing that causes because of spread of voltage that external power supply provides.Simultaneously; Also there is certain defective in this patent: because the limitation of the coil working voltage of relay, system allows the supply voltage of input narrow, along with the variation of system's input supply voltage; Relay can not adapt to system's input power supply of other scopes; In addition, the work of the auxiliary switch mechanical type of relay causes the circuit system reliability to reduce.

The utility model content

In view of this, the purpose of the utility model is to provide a kind of back difference mode electric power management circuit of improvement, this circuit working wide ranges, reliability height.

In order to realize above purpose; The utility model adopts a kind of like this back difference mode electric power management circuit of improvement; Input power supply Uin is through resistance R 1, resistance R 2, resistance R 3 dividing potential drops; The tie point A of described resistance R 1 and described resistance R 2 is connected to the grid of switching tube Q1; The grid that drain electrode warp one resistance R 5 of described switching tube Q1 is connected to switching tube Q2 draws electricity from the tie point D of described resistance R 2 and described resistance R 3, is connected to the drain electrode of described switching tube Q2 and the startup end C of PWM controller through diode D1; The startup end C of described PWM controller and the drain electrode of described switching tube Q1 are connected to the positive pole of importing power supply Uin through starting resistance Ro and pull-up resistor R4 respectively, and the source electrode of described switching tube Q1, Q2 and the GND of described PWM controller end are connected to ground respectively.

Especially, capacitor C 1 also is connected to the grid source end of described switching tube Q1, and the grid source end of capacitor C 2, voltage-stabiliser tube Z1 and described switching tube Q2 is parallel connection one by one.

The difference of the utility model and prior art is: adopt the drain-source of switching tube Q2 to bring in auxiliary switch and the divider resistance R3 short circuit that replaces relay, simultaneously, the drain electrode of switching tube Q2 is connected with the startup end of PWM controller.This structure had both guaranteed that system's external power supply voltage had certain return difference getting between electric and the dead electricity of interior power supply circuit; The restriction and the work of auxiliary switch mechanical type of the coil working voltage of relay have been avoided again; Widen system's input supply voltage scope to a certain extent, improved reliability of products.

Description of drawings

Fig. 1 is a kind of back difference mode electric power management circuit schematic diagram in the prior art.

Fig. 2 is the back difference mode electric power management circuit schematic diagram of a kind of improvement of the utility model.

Embodiment

As shown in Figure 2; A kind of back difference mode electric power management circuit of improvement; Input power supply Uin is through resistance R 1, resistance R 2, resistance R 3 dividing potential drops, and the tie point A of resistance R 1 and resistance R 2 is connected to the grid of switching tube Q1, and the drain electrode of switching tube Q1 is connected to the grid of switching tube Q2 through a resistance R 5; The tie point D of self-resistance R2 and resistance R 3 draws; Be connected to the drain electrode of switching tube Q2 and the startup end C of PWM controller through diode D1, the startup end C of PWM controller and the drain electrode of switching tube Q1 are connected to the positive pole of importing power supply Uin through starting resistance Ro and pull-up resistor R4 respectively, and the GND end of the source electrode of switching tube Q1, Q2 and PWM controller is connected to ground respectively.Capacitor C 1 also is connected to the grid source end of switching tube Q1, and the grid source end of capacitor C 2, voltage-stabiliser tube Z1 and switching tube Q2 is parallel connection one by one.

The operation principle of this circuit: be enough to make switching tube Q1 conducting when the input power source voltage rises to, promptly $\mathrm{Ug}1=\mathrm{Uin}\left(\mathrm{On}\right)\frac{R2+R3}{R1+R2+R3}\≥\mathrm{Ugs}\left(\mathrm{On}\right),$ Switching tube Q1 conducting, the drain voltage of switching tube Q1 is dragged down, and switching tube Q2 turn-offs, and the voltage that the startup end C of PWM controller is ordered raises, and diode D is in blocking state, and the PWM controller in the system power supply circuit gets electric, and system starts working.When input supply voltage drops to a certain numerical value, switching tube Q1 turn-offs, switching tube Q2 conducting; The voltage that the startup end C of PWM controller is ordered is dragged down, and the PWM controller in the power circuit quits work, simultaneously; The voltage of related tie point D is dragged down, and divider resistance R3 has been changed the grid dividing potential drop coefficient of switching tube Q1 thus by short circuit; At this moment, can get $\frac{\mathrm{Uin}\left(\mathrm{On}\right)}{\mathrm{Uin}\left(\mathrm{Off}\right)}=\frac{R2+R3}{R1+R2+R3}/\frac{R2}{R1+R2}\≥1,$ Here, Uin (on) is that instruction PWM controller gets electric input power supply threshold voltage, and Uin (off) is the input power supply threshold voltage of instruction PWM controller dead electricity.This utility model whole circuit adopts electronic type noncontacting switch, reliable operation, it is wide to adapt to operating voltage range, and guaranteed that order back level power supply circuit powers on and the input power supply threshold voltage of power down between certain return difference is arranged.

Claims (2)

1. the back difference mode electric power management circuit of an improvement; It is characterized in that: input power supply (Uin) is through resistance (R1), resistance (R2), resistance (R3) dividing potential drop; The tie point (A) of described resistance (R1) and described resistance (R2) is connected to the grid of switching tube (Q1); The drain electrode of described switching tube (Q1) is connected to the grid of switching tube (Q2) through a resistance (R5); Tie point (D) from described resistance (R2) and described resistance (R3) draws; Be connected to the drain electrode of described switching tube (Q2) and the startup end (C) of PWM controller through diode (D1), the startup end (C) of described PWM controller and the drain electrode of described switching tube (Q1) are connected to the positive pole of importing power supply (Uin) through starting resistance (Ro) and pull-up resistor (R4) respectively, and the source electrode of described switching tube (Q1, Q2) and the GND of described PWM controller end are connected to ground respectively.

2. the back difference mode electric power management circuit of improvement according to claim 1 is characterized in that: electric capacity (C1) also is connected to the grid source end of described switching tube (Q1), and the grid source end of electric capacity (C2), voltage-stabiliser tube (Z1) and described switching tube (Q2) is parallel connection one by one.

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