Summary of the invention
The object of the present invention is to provide a kind of emergency power supply.It can judge the positive-negative polarity that battery connects automatically with after device battery is connected, and correct current output signal is provided then, and is convenient to use, has improved operability.
For achieving the above object, the invention provides a kind of emergency power supply, it comprises a control circuit and a storage battery that circuit connects; Described control circuit comprises the external cell testing circuit of circuit connection successively, drive logic, and the reversal connection circuit charges and controls and the battery electric quantity testing circuit automatically;
Described external cell testing circuit, drive logic, automatic reversal connection circuit, charging control and battery electric quantity testing circuit also connect a single-chip microcomputer respectively;
Described drive logic (H bridge circuit) comprises high-end drive circuit and low-side driver circuitry;
Described drive logic also comprises current-limiting protection circuit, and its PWM by single-chip microcomputer (pulse width modulation) controls realization;
Described automatic reversal connection circuit is made up of some MOSFET (mos field effect transistor); Comprise some MOSFET that drive by the forward logical signal and the some MOSFET that drive by the reverse logic signal;
Described control circuit also comprises guardtime circuit and thermal-shutdown circuit; Described guardtime circuit is by Single-chip Controlling; Described thermal-shutdown circuit is connected with single-chip microcomputer.
The operation principle of emergency power supply provided by the invention is as follows:
When this emergency power supply with after device battery is connected, the external cell testing circuit is judged the connection of battery polar, at first, can produce a bias voltage during this external cell testing circuit, and send this bias voltage to single-chip microcomputer, after single-chip microcomputer receives this biasing voltage signal, judge the positive-negative polarity that emergency power supply is connected with device battery again; When emergency power supply and device battery were just connecing, the external cell testing circuit was 0 at the voltage of signal output part, and after single-chip microcomputer received this signal, single-chip microcomputer was operated in the forward operating state; When emergency power supply and device battery reversal connection, the output of external cell testing circuit produces a magnitude of voltage, and after single-chip microcomputer received this voltage signal, single-chip microcomputer was operated in the reverse operation state;
Single-chip microcomputer provides correct logical drive signal to give high-end drive circuit and low-side driver circuitry respectively, and this correct logical drive signal can guarantee the reliable driving of high-end drive circuit output and the reliable driving of low-side driver circuitry output;
Simultaneously, after H bridge drive logic is driven by the logical drive signal, flow through owing to have sizable electric current, carry out current-limiting protection so be provided with current-limiting protection circuit, this current-limiting protection circuit is to be realized by the PWM of single-chip microcomputer (pulse width modulation) control; To H bridge current sampling, the current signal that obtains amplifies through amplifier, exports to single-chip microcomputer, and the corresponding PWM waveform of output; If when single-chip microcomputer detected and to obtain that this moment, H bridge electric current was lower than rated current, PWM did not work, and this current value is fully exported; When if single-chip microcomputer detects and to obtain that this moment, H bridge electric current was higher than rated current, PWM recently controls the ON time of the grid of the MOSFET in the H bridge drive logic by the control duty, described duty ratio, be meant the ratio that high level occupies in the unit period, if duty ratio is more little, be that the average current of conducting is more little in the unit interval, the electric current that MOSFET carried is just more little thus, so just make the electric current that flows through reach maximum, but keep average current constant, play the effect of protection MOSFET;
The drive signal of drive logic output is sent to automatic reversal connection circuit, the signal indicating emergency power supply and the device battery that receive when this automatic reversal connection circuit are the states that just connecing, show that drive logic provides the forward logical signal, automatically the some MOSFET that driven by the forward logical signal in the reversal connection circuit are connected conducting, and export this signal to single-chip microcomputer; The signal indicating emergency power supply and the device battery that receive when this automatic reversal connection circuit are the reversal connection states, show that drive logic provides the reverse logic signal, automatically the some MOSFET that driven by the reverse logic signal in the reversal connection circuit are connected conducting, and export this signal to single-chip microcomputer;
After single-chip microcomputer receives correct logical signal, start charging control and the work of battery electric quantity testing circuit; Charging control and battery electric quantity testing circuit detect the magnitude of voltage of current device battery, and it is inputed to single-chip microcomputer, press the magnitude of voltage that testing button just can show present device battery again, simultaneously, set according to the quantification to magnitude of voltage in advance, corresponding meeting shows the magnitude of voltage of present device battery is in which state in " high, medium and low "; If when detecting the electric weight deficiency that obtains the current device battery, 12 pairs of device batteries of storage battery charge, and auxiliary current is provided; In charging process, when the voltage of display device battery is higher than the charging voltage thresholding that sets in advance, charged state is converted to floating charge state, i.e. low current charge state, and have corresponding indicator light to show this information.
The control circuit of emergency power supply provided by the invention also comprises guardtime circuit and thermal-shutdown circuit; This guardtime circuit is realized by Single-chip Controlling, can one set point be set earlier according to actual conditions in single-chip microcomputer, emergency power supply is started working, single-chip microcomputer just picks up counting, when the operating time of emergency power supply reaches this set point, emergency power supply just quits work automatically, restarts after rest a period of time again and starts working; This thermal-shutdown circuit adopts the resistance of negative temperature coefficient as its thermistor; the voltage that detection is obtained inputs to single-chip microcomputer; single-chip microcomputer is according to the temperature of the current voltage value decision circuitry that receives; in case when finding that the current temperature of this emergency power supply is higher than normal value; single-chip microcomputer makes this emergency power supply quit work immediately; recover normal up to its temperature, reset automatically again, start working.
Emergency power supply provided by the invention, can judge automatically that it is connected with the positive-negative polarity of device battery, no matter current connection correctness, no matter promptly this emergency power supply and device battery are just to connect or reversal connection, it can both provide correct output signal, makes the current electric quantity of this emergency power supply energy checkout equipment battery, and when the current electric quantity deficiency of device battery, it is charged, make the equipment operate as normal.
Emergency power supply provided by the invention, easy to use, have very strong operability, and when this emergency power supply work, the state of supervisory circuit there is stronger self-protection ability constantly.Be particularly useful for automobile industry, be used for automobile batteries is charged, and when automobile starting for automobile provides enough big startup auxiliary current, realize the final startup of automobile.
Embodiment
Following according to Fig. 1~Fig. 8, a preferred forms of the present invention is described.
As shown in Figure 1, be the fundamental diagram of the automatic reversal connection of emergency power supply provided by the invention, it comprises control circuit and internal battery 12 that circuit connects; As shown in Figure 2, be the circuit block diagram of the control circuit of emergency power supply provided by the invention, this control circuit comprises the external cell testing circuit 101 that circuit successively connects, drive logic 102, automatically reversal connection circuit 103 charges and controls and battery electric quantity testing circuit 104;
Described external cell testing circuit 101, drive logic 102, automatic reversal connection circuit 103, charging control and battery electric quantity testing circuit 104 are gone back circuit respectively and are connected a single-chip microcomputer (not illustrating in the drawings);
Described drive logic 102 (H bridge circuit), it comprises high-end drive circuit 1021 (as Fig. 4) and low-side driver circuitry 1022 (as Fig. 5);
Described automatic reversal connection circuit is made up of some MOSFET (mos field effect transistor); Comprise some MOSFET that drive by the forward logical signal and the some MOSFET that drive by the reverse logic signal;
Described drive logic 102 also comprises current-limiting protection circuit 1023 (as Fig. 6), and its PWM by single-chip microcomputer (pulse width modulation) controls realization;
Described control circuit also comprises guardtime circuit and thermal-shutdown circuit 105; Described guardtime circuit is by Single-chip Controlling; Described thermal-shutdown circuit 105 is connected with single-chip microcomputer.
The operation principle of emergency power supply provided by the invention is as follows:
As shown in Figure 3, be external cell testing circuit 101 circuit diagrams of emergency power supply provided by the invention, the connection of 101 pairs of battery polars of this external cell testing circuit is judged; Described external cell testing circuit 101 comprises the diode comparison circuit 1011 that circuit connects, and bias-voltage generating circuit 1012 and conduction voltage drop produce circuit 1013; Described diode comparison circuit 1011 comprises comparator U1A and U1B and diode D1 and D2; The output of comparator U1A is connected with the anode of diode D1, with the voltage signal that the input A that compares external cell testing circuit 101 is ordered, whether determines diode D1 conducting; The output of comparator U1B is connected with the anode of diode D2; With the voltage signal that the input B that compares external cell testing circuit 101 is ordered, whether determine diode D2 conducting; Described bias-voltage generating circuit 1012 comprises triode A1, produces bias voltage at the output D of bias-voltage generating circuit 1012 point; Described conduction voltage drop produces the signal generation conduction voltage drop of circuit 1013 according to diode comparison circuit 1011;
When emergency power supply and automobile batteries were just connecing, promptly the A point connect positive pole, and the B point connects negative pole, diode D1 conducting this moment, diode D2 by, so be zero conduction voltage drop in the C point value of obtaining, simultaneously because triode A1 conducting, so on the D point, can produce a bias voltage, this bias voltage sends single-chip microcomputer to, after single-chip microcomputer receives this biasing voltage signal, receives the conduction voltage drop zero that C is ordered, judge this moment emergency power supply and automobile batteries and just connect, so this single-chip microcomputer is operated in the forward operating state; When this emergency power supply and automobile batteries reversal connection, be that the A point connects negative pole, the B point connects positive pole, diode D2 conducting this moment, diode D1 ends, so can obtain a magnitude of voltage at the C point be+5V, produce a bias voltage at the D point simultaneously, this bias voltage sends single-chip microcomputer to, after single-chip microcomputer receives this biasing voltage signal, receive conduction voltage drop+5V that C is ordered, judge emergency power supply and automobile batteries reversal connection at this moment, so this single-chip microcomputer is operated in the forward operating state.And when 2 of A, B did not connect external cell, this circuit was not worked, so if directly 2 short circuits of A, B can not caused yet circuit to damage because of carelessness, can avoid the output short circuit of this circuit.
Single-chip microcomputer provides correct logical drive signal to give high-end drive circuit and low-side driver circuitry respectively, and this correct logical drive signal can guarantee the reliable driving of high-end drive circuit output and the reliable driving of low-side driver circuitry output;
As shown in Figure 4, be the circuit diagram of the high-end drive circuit 1021 of emergency power supply provided by the invention, described high-end drive circuit 1021 comprises high-end power supply active circuit 10211, forward drive transistor circuit 10212 and reverse drive transistor circuit 10213; Described high-end power supply active circuit 10211 comprises a high-side driver chip U2, and the power supply of+12V activates high-side driver chip U2 work, output pulsed drive, turning circuit; When external cell testing circuit 101 is exported the forward logical signals to single-chip microcomputer, receive this forward logical signal by described forward drive transistor circuit 10212 from single-chip microcomputer, drive triode A2, at the voltage that produces on the high-end switch pipe Q1 about 25V, finally making high-end grid voltage pressure reduction is about 12V, drives high-end switch pipe Q1; When external cell testing circuit 101 is exported the reverse logic signals to single-chip microcomputer, receive this reverse logic signal by described reverse drive transistor circuit 10213 from single-chip microcomputer, drive triode A3, at the voltage that produces on the high-end switch pipe Q2 about 25V, finally making high-end grid voltage pressure reduction is about 12V, drives high-end switch pipe Q2.
As shown in Figure 5, be the circuit diagram of the low-side driver circuitry 1022 of emergency power supply provided by the invention, described low-side driver circuitry 1022 comprises low side power supply active circuit 10221, forward drive transistor circuit 10222 and reverse drive transistor circuit 10223; In the described low side power supply active circuit 10221, the conducting of+12V power supply active circuit; When external cell testing circuit 101 is exported the forward logical signals to single-chip microcomputer, receive the forward logical signal by described forward drive transistor circuit 10222 from single-chip microcomputer, drive triode A4, at the voltage that produces on the low-end switch pipe Q4 about 25V, finally making low side grid voltage pressure reduction is about 12V, drives high-end switch pipe Q4; When external cell testing circuit 101 is exported the reverse logic signals to single-chip microcomputer, receive the reverse logic signal by described reverse drive transistor circuit 10223 from single-chip microcomputer, drive triode A5, at the voltage that produces on the high-end switch pipe Q3 about 25V, finally making low side grid voltage pressure reduction is about 12V, drives high-end switch pipe Q3.
Simultaneously, after H bridge drive logic is driven by the logical drive signal, because having sizable electric current flows through, and carries out current-limiting protection so be provided with current-limiting protection circuit, this current-limiting protection circuit 1023 is PWM (pulse width modulation) the control realizations by single-chip microcomputer; As shown in Figure 6, for the circuit diagram of the current-limiting protection circuit 1023 of emergency power supply provided by the invention, H bridge electric current is taken a sample, the current signal that obtains amplifies through the two poles of the earth amplifier, exports to single-chip microcomputer, and the corresponding PWM waveform of output; If when single-chip microcomputer detected and to obtain that this moment, H bridge electric current was lower than rated current, PWM did not work, and this current value is fully exported; When if single-chip microcomputer detects and to obtain that this moment, H bridge electric current was higher than rated current, PR recently controls the ON time of the grid of the MOSFET (mos field effect transistor) in the H bridge drive logic by the control duty, described duty ratio, be meant the ratio that high level occupies in the unit period, if duty ratio is more little, be that the average current of conducting is more little in the unit interval, the electric current that MOSFET carried is just more little thus, so just make the electric current that flows through reach maximum, but keep average current constant, play the effect of the MOSFET in the protection H bridge drive logic;
H bridge drive logic 102 outputs (Q1 among Fig. 4, Q2, Q3 among Fig. 5, Q4) output drive signal be sent to automatic reversal connection circuit 103, as shown in Figure 1, the signal indicating emergency power supply and the device battery that receive when this automatic reversal connection circuit 103 are the states that just connecing, show that drive logic 102 provides the forward logical signal, automatically the MOSFET M1 that is driven by the forward logical signal in the reversal connection circuit 103 is connected conducting with MOSFET M4, and exports this signal to single-chip microcomputer; The signal indicating emergency power supply and the device battery that receive when this automatic reversal connection circuit 103 are the reversal connection states, show that drive logic 102 provides the reverse logic signal, automatically the MOSFET M2 that is driven by the reverse logic signal in the reversal connection circuit 103 is connected conducting with MOSFET M3, and exports this signal to single-chip microcomputer;
After single-chip microcomputer receives correct logical signal, start charging control and 104 work of battery electric quantity testing circuit; As shown in Figure 7, charging control and battery electric quantity testing circuit 104 detect the magnitude of voltage of current automobile batteries, and it is inputed to single-chip microcomputer, press the magnitude of voltage that testing button just can show present automobile batteries again, simultaneously, set according to the quantification to magnitude of voltage in advance, corresponding meeting shows the magnitude of voltage of present automobile batteries is in which state in " high, medium and low "; If when detecting the electric weight deficiency that obtains current automobile batteries, 12 pairs of automobile batteriess of storage battery charge, and auxiliary current is provided; In charging process, when the voltage of display automobile battery is higher than the charging voltage thresholding that sets in advance, charged state is converted to floating charge state, be low current charge state (being generally several milliamperes), and have corresponding indicator light to show this information.
The control circuit of emergency power supply provided by the invention also comprises guardtime circuit and thermal-shutdown circuit; This guardtime circuit is realized by Single-chip Controlling, can one set point be set earlier according to actual conditions in single-chip microcomputer, emergency power supply is started working, single-chip microcomputer just picks up counting, when the operating time of emergency power supply reaches this set point, emergency power supply just quits work automatically, restarts after rest a period of time again and starts working; As shown in Figure 8; circuit diagram for thermal-shutdown circuit 105; this thermal-shutdown circuit adopts the resistance of negative temperature coefficient as its thermistor, AD1, and AD2 detects the voltage that obtains and inputs to single-chip microcomputer; single-chip microcomputer is according to the temperature of the current voltage value decision circuitry that receives; in case when finding that the current temperature of this emergency power supply is higher than normal value, single-chip microcomputer makes this emergency power supply quit work immediately, recover normal up to its temperature; reset automatically again, start working.
Emergency power supply provided by the invention, can judge automatically that it is connected with the positive-negative polarity of automobile batteries, no matter current connection correctness, no matter promptly this emergency power supply and automobile batteries are just to connect or reversal connection, it can both provide correct output signal, makes this emergency power supply can detect the current electric quantity of automobile batteries, and when the current electric quantity deficiency of automobile batteries, it is charged, when automobile starting,, realize the final startup of automobile for automobile provides enough big startup auxiliary current.
Emergency power supply provided by the invention, easy to use, have very strong operability, and when this emergency power supply work, the state of supervisory circuit there is stronger self-protection ability constantly.