TWI383560B - Power apparatus and protecting method thereof - Google Patents

Description

Power supply device and protection method thereof

The invention relates to a power supply circuit, in particular to a power supply device with two power inputs of a battery and a power adapter and a protection method thereof.

With the miniaturization and portability of electronic products, many electronic products are battery-powered, such as portable DVDs, mobile phones, and notebook computers. These products are usually battery-powered and have an external power supply, such as powering electronic devices through a power adapter or USB interface.

Usually, when the external power supply and the battery are simultaneously connected, the external power supply will supply power to the electronic device, and the external power supply further charges the battery. However, when only the external power supply is connected, and there is no battery access, since the access terminals for connecting the various contacts of the battery on the electronic device are relatively close, the mixed impurities or the faulty battery may cause the system to be short-circuited. Safety accidents such as fire and smoke may occur.

In view of this, it is necessary to provide a safe power supply unit.

It is also necessary to provide a method of protecting the power supply unit.

A power supply device includes a power access unit for inputting an external power source and a battery access unit for inputting battery power. The power supply device further includes an unlocking/charging switch and a control unit connected between the power access unit and the battery access unit for controlling the power based on its own closing and opening Turning on and off between the source access unit and the battery access unit, the control unit is configured to control when the power access unit receives an input of the external power source and the battery access unit does not receive the input of the battery power source The unlock/charge switch is intermittently turned on.

A power device protection method includes the following steps: detecting whether an external power source is connected; if an external power source is connected, detecting whether a battery is connected; if no battery power is connected, sending an intermittent communication number to enable an external power source and a battery The access terminals are intermittently turned on to unlock the battery that may be accessed; if there is battery power access, a continuous conduction communication number is sent, so that the external power supply and the battery access terminal are continuously turned on to charge the battery.

The above power supply device and the protection method thereof use the intermittent conduction mode to unlock the battery that may be accessed before detecting the battery access, thereby avoiding the continuous conduction of the battery related circuit, and effectively reducing the system damage caused by the short circuit of the battery related circuit. It also ensures the normal operation of the battery related circuit after the battery is connected midway.

Please refer to FIG. 1 and FIG. 2 , which are a block diagram and a circuit diagram of a power supply device 10 according to a preferred embodiment, including: a power access unit 102, a battery access unit 104, a power supply selection unit 106, and an unlock/charge switch. 108. The control unit 110, the first conversion circuit 112, and the second conversion circuit 114.

The power access unit 102 is configured to receive an input of an external power supply AD VCC, such as Input of the power adapter, etc.

The battery access unit 104 is a battery case for input of the battery power source BT VCC. The battery usually has four terminals: the power output, the unlock/charge terminal, the battery status output, and the ground. The battery access unit 104 is provided with four connection terminals corresponding to four terminals of the battery: a power supply terminal A, a control terminal B, a state detection terminal C, and a ground terminal D. The power terminal A corresponds to the power output end of the battery; the control terminal B corresponds to the unlocking/charging end of the battery; the state detecting terminal C corresponds to the battery state output end of the battery; the ground terminal D corresponds to the ground terminal of the battery. The power access unit 102 and the power terminal A are respectively connected to the power supply selection unit 106; the power source access unit 102 is connected to the control terminal B by the unlocking/charging switch 108; in this embodiment, the state detecting terminal C is not involved, so in FIG. 2 The status detection terminal C has no connection; the ground terminal D is grounded. The battery is unlocked because the battery is usually provided with a protection circuit, and enters a locked state under abnormal conditions such as over-discharge or internal short-circuit of the battery, that is, the power supply terminal A of the battery has no voltage output, and only the control terminal B receives a high level. After that, the battery is unlocked and put into normal working condition.

The power supply selection unit 106 is configured to select one of the external power supply AD VCC and the battery power supply BT VCC to provide the system power supply DC IN for the electronic device.

The unlock/charge switch 108 is a switch that is connected to the power supply access unit 102 and the control terminal B of the battery access unit 104 to control electrical conduction and disconnection therebetween.

The first conversion circuit 112 is connected between the power supply access unit 102 and the control unit 110 for converting the voltage input from the power supply access unit 102 (ie, the external power supply AD VCC) into a first voltage that the control unit 110 can accept. .

The second conversion circuit 114 is connected between the power terminal A of the battery access unit 104 and the control unit 110 for converting the voltage input from the power terminal A (ie, the battery power source BT VCC) into a second acceptable to the control unit 110. Voltage.

The control unit 110 is configured to control the closing and opening of the unlocking/charging switch 108 according to the first voltage and the second voltage, that is, controlling the electrical conduction and disconnection of the power supply access unit 102 and the control terminal B of the battery access unit 104. open. The control unit 110 includes a power detection device 122, a battery detector 124, and a signal generator 126. The power detecting device 122 is configured to detect the first voltage and generate a first detecting signal to determine whether the external power source AD VCC is connected to the power access unit 102. The battery detector 124 is configured to detect the second voltage and generate a second detection signal to determine whether there is an input of the battery power source BT VCC on the battery access unit 104, that is, whether there is a battery. The signal generator 126 is configured to generate a control signal according to the first detection signal and the second detection signal for controlling the closing and opening of the unlock/charge switch 108. The control signal includes an intermittent pilot number and a continuous pilot number. Wherein, when the access of the external power supply AD VCC is detected, but the battery power supply BT VCC is not detected, the signal generator 126 sends an intermittent conduction communication number, so that the unlocking/charging switch 108 is turned on and off, such as intermittent. The pilot signal is a pulse signal of positive 2 seconds minus 4 seconds, that is, the unlock/charge switch 108 is turned on for 2 seconds and then turned off for 4 seconds. When the access of the external power supply AD VCC is detected and the battery power supply BT VCC is also detected, the signal generator 126 issues a continuous communication number to keep the unlock/charge switch 108 continuously turned on.

The reason why the above signal generator 126 sends the intermittent communication number is: The battery is not detected when accessing, but the battery may be in a protected state, or there may be no battery access, and the user may install the battery at any time. To this end, it is necessary to intermittently turn on the unlock/charge switch 108 so that the external power supply AD VCC intermittently supplies a high level to the control terminal B of the battery access unit 104 for unlocking the battery that may be accessed. If there is a battery access during this period, the battery is unlocked by the intermittent communication number, so that the battery detector 124 detects that the power terminal A of the battery access unit 104 has the input of the battery power BT VCC, and the signal generator 126 sends a continuous communication number. The unlock/charge switch 108 is continuously turned on, and the external power supply AD VCC charges the battery by the unlock/charge switch 108 and the control terminal B. If the battery power supply BT VCC has not been detected, the intermittent unlocking operation continues. If the power supply terminal A and the control terminal B on the battery access unit 104 are turned on due to the incorporation of impurities, the system will only be intermittent. Short circuit will not cause substantial damage to the system. It can be seen that different intermittent conduction times can be set according to different systems. It can be seen that the above-mentioned power supply device 10 protects the system security of the electronic device, and ensures normal charging after the battery is connected in the middle, and even the battery is locked.

Referring further to FIG. 2, the power supply selection unit 106 includes a resistor R1, a diode D1, and a P-channel field effect transistor Q1 integrated with a diode, also referred to as an IGBT, such as a field effect transistor of the type NTS4101P-D. The gate of the FET Q1 is connected to the power supply access unit 102 via a resistor R1. The source of the FET Q1 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to the power source access unit 102. The drain of the FET Q1 is connected to the power supply terminal A of the battery access unit 104 (corresponding to the output of the battery). The system power supply DC IN is obtained from the source of the FET Q1.

The unlock/charge switch 108 includes three resistors R2, R3, R4, a transistor T1, and a P-channel field effect transistor Q2 integrated with a diode. The collector of the transistor T1 is connected to the power supply access unit 102 via a resistor R2. The base of the transistor T1 is connected to the control unit 110 via a resistor R3, and the base of the transistor T1 is grounded via a resistor R4. The emitter of transistor T1 is grounded. The source of the FET Q2 is connected to the power supply access unit 102. The drain of the FET Q2 is connected to the control terminal B of the battery access unit 104 (corresponding to the unlock/charge terminal of the battery). The gate of the field effect transistor Q2 is connected to the emitter of the transistor T1.

The first conversion circuit 112 includes three resistors R5, R6, and R7 and two capacitors C1 and C2. The power access unit 102, the resistors R5, R6, and the control unit 110 are connected in series. One ends of the two capacitors C1 and C2 are respectively connected to both ends of the resistor R6, and the other end is grounded. Resistor R7 is connected in parallel with capacitor C1.

The second conversion circuit 114 includes two resistors R8, R9 and two capacitors C3, C4. The power terminal A of the battery access unit 104, the two resistors R8, R9 and the ground are connected in series. The control unit 110 is connected between the two resistors R8, R9. The two capacitors C3 and C4 are respectively connected in parallel with the resistor R9.

In this embodiment, the control unit 110 is a single chip microcomputer. For example, in the Z8F0822 chip, the first conversion circuit 112 is connected to the 13th pin of the Z8F0822 chip to determine whether there is an input of the external power supply AD VCC by the detection of the high and low levels. The second conversion circuit 114 is connected to the 28th pin of the Z8F0822 chip, and is also judged by the high and low level detection whether there is an input of the battery power BT VCC. Pin 12 of the Z8F0822 chip is connected to the unlock/charge switch 108 and outputs a control signal from pin 12. The control unit 110 can also use other various programmable chips or other circuit designs, as long as it can distinguish two high and low levels and can send control signals.

When only the battery is connected, the FET Q1 is turned on, the system power supply DC IN is provided by the battery, and the diode D1 is used to prevent the battery power BT VCC from flowing to the power access unit 102. When there is an external power supply AD VCC input, the FET Q1 is turned off, and the system power supply DC IN is supplied by the external power supply AD VCC regardless of whether or not there is a battery access. After the external power supply AD VCC is connected, the voltage is filtered by the resistors R5, R6, and R7 and the two capacitors C1 and C2, so that the control unit 110 detects a stable first voltage. The control unit 110 determines that the external power supply AD VCC is connected according to the first voltage, and sends an intermittent conduction communication number, such as a pulse signal, so that the transistor T1 and the FET Q2 are simultaneously turned on intermittently to unlock the battery that may be accessed. At this time, if there is a battery access, first unlock the battery by intermittent communication number (if the battery itself does not protect or affect the circuit operation), use the voltage divider and filter of the resistors R8, R9, capacitors C3, C4 to filter the battery The power supply BT VCC is converted to a stable second voltage. The control unit 110 determines that there is a battery access according to the second voltage, and issues a continuous conduction communication number, and the external power supply AD VCC continuously charges the battery.

Please refer to FIG. 3 , which is a flowchart of a method for protecting a power supply device according to a preferred embodiment, including the following steps:

Step S301, detecting whether there is external power supply access, if yes, proceeding to step S303, if not, continuing to detect whether there is external power supply access.

In step S303, the system is powered by an external power source.

In step S305, it is detected whether there is a battery access, and if so, the process proceeds to step S309, and if not, the process proceeds to step S307.

Step S307, sending an intermittent communication number to connect the external power source to the battery The terminals are intermittently turned on to unlock the battery that may be accessed, and then return to step S305. In other embodiments, the process may return to step S301.

Step S309, sending a continuous conduction communication number to continuously conduct the external power source and the battery access terminal to charge the battery.

The power supply device protection method unlocks the potentially accessible battery by intermittent conduction before detecting the battery access, thereby avoiding continuous conduction of the battery related circuit, and effectively reducing system damage caused by short circuit of the battery related circuit. In addition, the method ensures that the charging operation after the battery is accessed midway is normal.

10‧‧‧Power supply unit

AD VCC‧‧‧ external power supply

102‧‧‧Power access unit

BT VCC‧‧‧Battery Power Supply

104‧‧‧Battery access unit

DC IN‧‧‧ system power supply

106‧‧‧Power supply selection unit

D1‧‧‧ diode

108‧‧‧Unlock/Charge Switch

Q1, Q2‧‧‧ FET

110‧‧‧Control unit

T1‧‧‧ triode

112‧‧‧First conversion circuit

C1, C2, C3, C4‧‧‧ capacitors

114‧‧‧Second conversion circuit

A‧‧‧Power terminal

122‧‧‧Power detection appliances

B‧‧‧Control terminal

124‧‧‧Battery detector

C‧‧‧Status detection terminal

126‧‧‧Signal Generator

D‧‧‧ Grounding terminal

R1, R2, R3, R4, R5, R6, R7, R8, R9‧‧‧ resistors

S301~S309‧‧‧Power device protection method

1 is a functional block diagram of a power supply device according to a preferred embodiment.

Fig. 2 is a circuit diagram of the power supply unit shown in Fig. 1.

FIG. 3 is a diagram of a method of protecting a power supply device according to a preferred embodiment.

10‧‧‧Power supply unit

112‧‧‧First conversion circuit

102‧‧‧Power access unit

114‧‧‧Second conversion circuit

104‧‧‧Battery access unit

122‧‧‧Power detection appliances

106‧‧‧Power supply selection unit

124‧‧‧Battery detector

108‧‧‧Unlock/Charge Switch

126‧‧‧Signal Generator

110‧‧‧Control unit

Claims (10)

A power supply device includes a power access unit and a battery access unit, wherein the power access unit is electrically connected to an external power source and receives an input of an external power source, and the battery access unit is configured to be electrically connected to the battery power source. Receiving an input of battery power, the improvement is that the power supply device further includes an unlock/charge switch and a control unit connected between the power access unit and the battery access unit for closing based on itself Disabling the conduction and disconnection between the control power access unit and the battery access unit, the control unit is configured to receive an input of the external power source at the power access unit and the battery access unit does not receive the input of the battery power Controlling the unlock/charge switch to be intermittently turned on; during the turn-on/charge switch being turned on, the external power source unlocks the battery that is electrically connected to the battery access unit and is in a locked state by the unlock/charge switch, and the battery is in the There is no voltage output when the state is locked. The power supply device of claim 1, wherein the control unit further receives an external power input at the power access unit, and the battery access unit also controls the unlock/charge switch to continue when receiving the battery power input. Turn on. The power supply device of claim 2, wherein the control unit comprises a power source detector, a battery detector, and a signal generator, wherein the power source detector is configured to detect and determine whether the power access unit has an input of an external power source, The battery detector is configured to detect and determine whether the battery access unit has an input of battery power. The signal generator is configured to send a control signal to the unlock/charge switch according to the detection result of the power source detector and the battery detector, and the control signal includes intermittent conduction. Signal and continuous communication number to control the solution separately The lock/charge switch is intermittently turned on and continuously turned on. The power supply device of claim 1, wherein the power supply device further includes a first conversion circuit and a second conversion circuit, wherein the first conversion circuit is configured to convert the external power supply into a first voltage acceptable to the control unit, The second conversion circuit is configured to convert the battery power into a second voltage acceptable by the control unit, and the control unit is configured to determine, according to the first voltage and the second voltage, whether there is an input of an external power source and a battery power source. The power supply device of claim 4, wherein the first conversion circuit and the second conversion circuit are voltage dividing filter circuits composed of a resistor and a capacitor. The power supply device of claim 1, wherein the power supply device further comprises a power supply selection unit for selecting one of an external power source and a battery power source to provide system power for the electronic device. The power supply device of claim 6, wherein the power supply selection unit comprises a resistor (R1), a diode (D1), and a P-channel field effect transistor (Q1), a gate of the field effect transistor (Q1). Connected to the power supply access unit via a resistor (R1), the source of the FET (Q1) is connected to the cathode of the diode (D1), and the anode of the diode (D1) is connected to the power supply access unit. The drain of the tube (Q1) is connected to the power supply terminal of the battery access unit, and the power connection terminal corresponds to the output end of the battery, and the system power is obtained from the source of the field effect transistor (Q1). The power supply device of claim 1, wherein the unlocking/charging switch comprises a resistor (R2), a triode (T1), and a P-channel field effect transistor (Q2), and a collector of the transistor (T1) is provided with a resistor ( R2) is connected to the power access unit, the base of the triode (T1) is connected to the control unit, the emitter of the triode (T1) is grounded, the source of the FET (Q2) is connected to the power access unit, and the field effect transistor ( Q2) drain and battery access unit The control terminal is connected, the control terminal corresponds to the unlocking/charging end of the battery, and the gate of the FET (Q2) is connected to the emitter of the triode (T1). A power device protection method includes the following steps: detecting whether an external power source is connected; if an external power source is connected, detecting whether a battery is connected; if no battery power is connected, sending an intermittent communication number to enable an external power source and a battery The access terminals are intermittently turned on. During the turn-on/charge switch is turned on, the external power source unlocks the battery that is electrically connected to the battery access unit and is in a locked state by the unlock/charge switch, and the battery is in a locked state. There is no voltage output; if there is battery power access, send a continuous communication number, so that the external power supply and the battery access terminal are continuously turned on to charge the battery. The power device protection method according to claim 9, wherein the power device protection method further comprises the following steps: if an external power source is connected, the system is powered by an external power source.