TWI639286B - Battery charge and discharge protection circuit - Google Patents

Abstract

The invention provides a battery protection circuit for protecting a battery from charging and discharging, wherein an end point of the battery protection circuit is connected to each other by a plurality of internal switches, and an external effect transistor is externally connected, and a source terminal and a drain terminal of the field effect transistor are connected to the battery. The charge and discharge paths, the gate terminal and the base terminal are controlled by a protection circuit. When the battery is charged abnormally, the protection circuit opens an internal switch, causing the gate terminal and the base terminal of the field effect transistor to be connected to the negative terminal of the battery package to terminate the charging operation. When the battery discharges an abnormal condition, the protection circuit opens another internal switch such that the gate terminal and the base terminal of the field effect transistor are connected to the negative terminal of the battery to terminate the discharge operation.

Description

Battery charging and discharging protection circuit

The present invention relates to a battery protection circuit. And in particular, a single transistor battery protection circuit for battery charging and discharging protection.

Battery protection circuits are widely used in a variety of electronic devices that require batteries, such as smart phones, tablets, and notebooks. There are four abnormal conditions that need to be protected by the battery: overcharging, overdischarging, excessive charging current, and excessive discharge current. During the charging process, if the battery voltage is higher than a certain value, it is judged to be overcharged. During the discharge process, if the battery voltage is lower than a certain value, it is judged to be excessively discharged. During the charging process, if the charging current is higher than a certain value, it is determined that the charging current is too large. During the discharge process, if the discharge current is higher than a certain value, it is determined that the discharge current is excessive. When any abnormal condition occurs, the battery protection circuit initiates a battery protection mechanism to terminate charging and discharging.

In the invention patent application No. I536694, a battery protection integrated circuit and a battery device are disclosed, wherein the battery protection integrated circuit includes a charging control terminal and a discharge control terminal, and two transistors are used to respectively control charging and discharging. path. When an abnormal condition such as overcharging, overdischarging, or excessive current occurs, the battery that controls the charging or the transistor that controls the discharge is turned off by controlling the voltage of the charging control terminal or the discharging control terminal to protect the battery from damage. However, this method requires the use of two transistors to increase the circuit area and cost. In addition, in normal mode, the two transistors are turned on. Cause more power loss.

In the invention patent application No. I445272 of Taiwan Patent, a switch embedded integrated circuit and method for protecting a battery is disclosed, wherein a MOS transistor having a base diode is connected to a path of charging and discharging of a battery, and The upper two switches switch the current direction of the base diode at both ends of the base diode, and control the gate of the MOS transistor with a third switch to provide protection functions for overcharge and overdischarge. However, this method requires a switch at both ends of the base diode, and a total of three control signals are required to control the MOS transistor, which makes the control logic circuit more complicated, and the switch at both ends of the base diode increases the circuit. Area and power loss.

In view of the above problems of the prior art, the present invention provides a battery protection circuit for battery charging and discharging protection, wherein each end of the battery protection circuit is connected by a plurality of internal switches, and only needs to be externally connected to the charging and discharging paths of the battery. A transistor and the cell protection circuit controls the gate and base terminals of the transistor. If there is an abnormal condition during charging or discharging of the battery, the protection circuit turns on the internal switch to control the gate terminal and the base terminal of the transistor, and terminates the charging or discharging action.

The invention provides a battery protection circuit comprising an input power terminal, a ground terminal, an output voltage terminal, a first control signal terminal and a second control signal terminal. The input power terminal is connected to a positive end of a battery; the ground end is connected to a negative end of the battery; the output voltage end is connected to a negative end or a positive end of a battery package; the first control signal end and the second control The signal end is used for controlling the charging and discharging paths of the battery, wherein the input power terminal, the ground terminal, the output voltage terminal, the first control signal end, and the second control signal end are transmitted through the complex Several switches are connected.

The battery protection circuit of the present invention further includes six switches connected between the five terminals, wherein the first switch is connected between the input power terminal and the output voltage terminal; the second switch is connected between the ground terminal and the output voltage terminal. a third switch is connected between the ground end and the second control signal end; the fourth switch is connected between the ground end and the first control signal end; the fifth switch is connected between the output voltage end and the second control signal end; The sixth switch is connected between the output voltage terminal and the first control signal terminal.

The battery protection circuit of the present invention turns on the third switch and the fourth switch in a normal state without any abnormality, and turns off the first switch, the second switch, the fifth switch, and the sixth switch. When the first control signal terminal is connected to the input power terminal (not the ground terminal), the battery is allowed to be normally charged and discharged.

The battery protection circuit of the present invention further includes an overcharge protection mode, in which the first switch, the fifth switch, and the sixth switch are turned on, and the second switch, the third switch, and the fourth switch are turned off, in an abnormal state of overcharging, In a state in which overcharging occurs during charging, the first control signal end and the second control signal end are connected to the negative end of the battery package or the positive end of the battery package through the output voltage terminal to protect the battery. When the battery voltage drops to a certain value or the load on the battery package end increases, the battery protection circuit will be released from protection.

The battery protection circuit of the present invention turns on the first switch, the third switch, and the fourth switch in an abnormal state of excessive discharge, and turns off the second switch, the fifth switch, and the sixth switch to protect the battery. In a state in which an overdischarge occurs during discharge, the first control signal end and the second control signal end are transmitted through the ground end, and are connected to the battery negative end or The positive end of the battery to protect the battery. When the battery voltage rises to a certain value or the charger is added to the battery package, the battery protection circuit will be released.

The battery protection circuit of the present invention turns on the first switch, the fifth switch, and the sixth switch in an abnormal state in which the charging current is excessively large, and turns off the second switch, the third switch, and the fourth switch to protect the battery. The first control signal end and the second control signal end are connected to the negative end of the battery package or the positive end of the battery package to protect the battery when the charging current is excessive during charging. When the charging current drops to a certain value or the charger on the battery package side is removed, the battery protection circuit will be unprotected.

The battery protection circuit of the present invention turns on the second switch, the third switch, and the fourth switch in an abnormal state in which the discharge current is excessively large, and turns off the first switch, the fifth switch, and the sixth switch to protect the battery. The first control signal end and the second control signal end are connected to the negative end of the battery or the positive end of the battery to protect the battery when the discharge current is excessive during discharge. When the discharge current drops to a certain value or the load on the battery package side is removed, the battery protection circuit will be released from protection.

The battery protection circuit of the present invention further includes an input power terminal, a ground terminal, an output voltage terminal, a first control signal terminal, and a second control signal terminal. The first control signal end and the second control signal end are connected to a single transistor that controls the charging and discharging paths.

According to the concept of the present invention, the transistor may be a field effect transistor, and the gate terminal of the field effect transistor is connected to the first control signal end of the battery protection circuit, and the base terminal of the field effect transistor is connected to the protection. The second control signal terminal of the circuit, the source terminal and the drain terminal of the field effect transistor are connected to the charging and discharging paths of the battery.

According to the concept of the present invention, the transistor is an N-type channel field effect transistor, and the gate terminal of the N-type channel field effect transistor is connected to the first control signal end, and the base terminal of the field effect transistor is connected to the The second control signal end, the source terminal and the 汲 terminal of the N-type channel field effect transistor are respectively connected to the negative end of the battery and the negative end of the battery package; the voltage output end of the battery protection circuit is connected to the negative end of the battery package.

The battery protection circuit of the present invention further includes one or more resistors connected in series between any of the terminals and any of the switches.

The internals of the battery protection circuit of the present invention are connected through a plurality of switches. This technical feature can also be applied to other battery protection circuits in which a plurality of transistors are connected in series, and is not limited to a battery protection circuit applied to an external single transistor.

The battery protection circuit of the invention adopts a connection method of an external single transistor, and the technical feature can also be applied to other battery protection circuits using different architectures, instead of being limited to a battery protection circuit that is internally connected through a plurality of switches. .

This paragraph of text extracts and compiles some of the features of the present invention; other features will be described in subsequent paragraphs. Its purpose is to cover the spirit and scope of the subsequent patent scope, different retouching and similar arrangements.

10‧‧‧Battery package

11‧‧‧Battery

12‧‧‧resistance

13‧‧‧ Capacitance

14‧‧‧Charger or load

15‧‧‧Battery front

16‧‧‧Battery negative

17‧‧‧The positive end of the battery package

18‧‧‧Battery package negative end

20‧‧‧Protection circuit

201‧‧‧Input power terminal

202‧‧‧ Grounding terminal

203‧‧‧Output voltage terminal

204‧‧‧First control signal terminal

205‧‧‧second control signal terminal

211‧‧‧ first switch

212‧‧‧Second switch

213‧‧‧ third switch

214‧‧‧fourth switch

215‧‧‧ fifth switch

216‧‧‧ sixth switch

30‧‧‧Optoelectronics

301‧‧‧Opto Gate Extreme

302‧‧‧Opto-based extremes

FIG. 1 is a circuit diagram showing a battery protection circuit architecture according to a first embodiment of the present invention.

The invention will be more clearly described with reference to the following examples. Please note that the following description of the embodiments of the present invention is intended to be illustrative only; this is not intended to be exhaustive The description or limitation is in the form of the disclosure.

Referring to FIG. 1 of a first embodiment of the present invention, a battery protection circuit architecture including a battery protection circuit 20 and a transistor 30 is shown. The battery protection circuit 20 includes an input power terminal 201, a ground terminal 202, an output voltage terminal 203, a first control signal terminal 204, and a second control signal terminal 205. The input power terminal 201 is connected to the battery positive terminal 15 through the resistor 12, and may also be directly connected without a resistor; the ground terminal 202 is directly connected to the battery negative terminal 16; the output voltage terminal 203 is directly connected to the battery package negative terminal 18, or through a The resistor is reconnected; the first control signal terminal 204 is coupled to the gate terminal 301 of the transistor; the second control signal terminal 205 is coupled to the base terminal 302 of the transistor. In addition, a capacitor 13 can be connected between the power terminal 201 and the ground terminal 202, and the battery package positive terminal 17 and the battery package negative terminal 18 can be connected to the charger or the load 14.

The battery protection circuit structure is shown in FIG. 1 , wherein the transistor 30 is an N-type MOS field-effect transistor (NMOS), and the source and the drain of the transistor 30 are respectively connected to the negative end of the battery and the battery package is negative. end.

The battery protection circuit 20 shown in FIG. 1 has six switches therein, wherein the first switch 211 is connected between the input power terminal 201 and the output voltage terminal 203; the second switch 212 is connected to the ground terminal 202 and the output voltage terminal 203. The third switch 213 is connected between the ground terminal 202 and the second control signal terminal 205; the fourth switch 214 is connected between the ground terminal 202 and the first control signal terminal 204; and the fifth switch 215 is connected to the output voltage terminal. Between the 203 and the second control signal terminal 205; the sixth switch 216 is connected between the output voltage terminal 203 and the first control signal terminal 204.

The battery protection circuit 20 shown in FIG. 1 turns on the third switch 213 and the fourth switch 214 in a normal state without any abnormality, and turns off the first switch 211 and the second switch. 212, a fifth switch 215 and a sixth switch 216. When the first control signal terminal 204 is connected to the battery positive terminal 15 (instead of the battery negative terminal 16), the battery 11 is allowed to be normally charged and discharged.

The battery protection circuit 20 shown in FIG. 1 turns on the first switch 211, the fifth switch 215, and the sixth switch 216, and turns off the second switch 212, the third switch 213, and the fourth in an abnormal state of overcharging. Switch 214 to protect battery 11. When the battery voltage drops to a certain value or the load on the battery package end increases, the battery protection circuit 20 will release the protection state.

The battery protection circuit 20 shown in FIG. 1 turns on the first switch 211, the third switch 213, and the fourth switch 214, and turns off the second switch 212, the fifth switch 215, and the sixth in an abnormal state of excessive discharge. Switch 216 to protect battery 11. The first control signal terminal 204 and the second control signal terminal 205 are connected to the battery negative terminal 16 or the battery positive terminal 15 through the ground terminal 202 to protect the battery 11 in the event of excessive discharge during discharge. When the battery voltage rises to a certain value or the charger is added to the battery package end, the battery protection circuit 20 will be released from the protection state.

The battery protection circuit 20 shown in FIG. 1 turns on the first switch 211, the fifth switch 215, and the sixth switch 216 in an abnormal state in which the charging current is excessively large, and turns off the second switch 212, the third switch 213, and the Four switches 214 are provided to protect the battery 11. When the charging current drops to a certain value or the charger at the battery package end is removed, the battery protection circuit 20 will be released from the protection state.

The battery protection circuit 20 shown in FIG. 1 turns on the second switch 212, the third switch 213, and the fourth switch 214 in an abnormal state in which the discharge current is excessively large, and turns off the first switch 211, the fifth switch 215, and the Six switches 216 protect the battery 11. Making it happen during discharge When the discharge current is too large, the first control signal terminal 204 and the second control signal terminal 205 are connected to the battery negative terminal 16 or the battery positive terminal 15 through the ground terminal 202 to protect the battery 11. When the discharge current drops to a certain value or the load on the battery package end is removed, the battery protection circuit 20 will be released from the protection state.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

Claims (10)

A battery protection circuit includes: an input power terminal connected to a positive end of a battery; a ground terminal connected to a negative end of the battery; and an output voltage terminal connected to a negative end of the battery package or positive a first control signal end and a second control signal end are used to control the charging and discharging paths of the battery; a first switch is connected between the input power terminal and the output voltage terminal; a second switch connected between the ground terminal and the output voltage terminal; a plurality of switches configured to connect the first control signal end and the second control signal end to the ground terminal and the output voltage terminal through the plurality of switches . The battery protection circuit of claim 1, wherein the plurality of switches comprise: a third switch connected between the ground end and the second control signal end; and a fourth switch connected to a grounding terminal and the first control signal end; a fifth switch connected between the output voltage terminal and the second control signal end; and a sixth switch connected to the output voltage terminal and the Between the first control signal terminals. The battery protection circuit of claim 2, further comprising an overcharge protection mode, the mode turning on the first switch, the fifth switch, and the sixth switch, and turning off the second switch, the third The switch and the fourth switch are configured to connect the first control signal end and the second control signal end to the negative end of the battery package through the output voltage terminal when the battery is overcharged during charging. The battery protection circuit of claim 2, further comprising an over-discharge protection mode, the mode turning on the first switch, the third switch, and the fourth switch, and turning off the second switch, the fifth The switch and the sixth switch are configured such that the first control signal end and the second control signal end pass through the ground end and are connected to the negative end of the battery in a condition of excessive discharge during discharge. The battery protection circuit of claim 2, further comprising a charging current over-protection mode, wherein the first switch, the fifth switch, and the sixth switch are turned on, and the second switch is turned off, the first The three switches and the fourth switch are configured to connect the first control signal end and the second control signal end to the negative terminal of the battery package through a state in which the charging current is excessive during charging. The battery protection circuit of claim 2, further comprising a discharge current over-protection mode, wherein the second switch, the third switch, and the fourth switch are turned on, and the first switch is turned off, the first switch The fifth switch and the sixth switch are configured such that the first control signal end and the second control signal end pass through the ground end and are connected to the negative end of the battery when the discharge current is excessively generated during discharge. A battery protection circuit includes: an input power terminal connected to a positive end of a battery; a ground terminal connected to a negative end of the battery; and an output voltage terminal connected to a negative end of the battery package or positive And a first control signal end and a second control signal end for controlling a charging and discharging path of the battery, wherein the input power terminal, the ground terminal, the output voltage terminal, and the first control signal end And the second control signal end is connected through a plurality of switches, And the first control signal end and the second control signal end are respectively connected to two end points of a single transistor that controls the charging and discharging paths. The battery protection circuit of claim 7, wherein the transistor is a field effect transistor, and a gate terminal of the field effect transistor is connected to the first control signal end of the protection circuit, the field effect transistor The base terminal is connected to the second control signal end of the protection circuit, and the source terminal and the drain terminal of the field effect transistor are connected to the charging and discharging paths of the battery. The battery protection circuit of claim 7, wherein the transistor is an N-type field effect transistor, and the gate terminal of the N-channel field effect transistor is connected to the first control signal of the protection circuit. The base end of the N-type field effect transistor is connected to the second control signal end of the protection circuit, and the source terminal and the 汲 terminal of the N-type channel field effect transistor are respectively connected to the negative end of the battery and the battery package is negative The voltage output terminal of the battery protection circuit is connected to the negative terminal of the battery package. The battery protection circuit as described in claim 1, item 2, item 3, item 4, item 5 or item 6 further includes one or more resistors connected in series to any of the terminals Between a switch.