CN208015445U - A kind of active and standby electric automatic switchover of fire alarm control unit, detection and protection circuit - Google Patents

Abstract

The utility model provides an automatic switchover, detection and protection circuit of main and backup power for a fire alarm controller, which comprises an automatic switchover circuit for main and backup power, a short-circuit open circuit detection circuit and a backup power protection circuit. The main and backup power automatic switching circuit includes the main power supply, lithium battery backup power supply, power switching chip and P-channel MOS tube, which can realize the main and backup power automatic switching; the short-circuit open circuit detection circuit includes the main power supply terminal voltage acquisition circuit and the lithium battery backup power supply terminal The voltage acquisition circuit can collect the voltage of the main power supply and the lithium battery backup power supply, and judge whether there is a short circuit or open circuit fault; the backup power protection circuit includes a lithium battery charge management chip, a diode and an N-channel MOS tube, which can realize charge and discharge protection . The utility model has fast switching action, no noise in the switching process, no voltage drop, no additional compensation circuit, low component cost, and greatly improves the working stability, reliability and safety of the lithium battery backup power supply.

Description

A fire alarm controller main and backup power automatic switching, detection and protection circuit

technical field

The utility model relates to the field of fire alarm controllers, in particular to an automatic switchover, detection and protection circuit of main and backup power of the fire alarm controller.

Background technique

Fire is ruthless and harmful. Many fires occur every year, causing huge losses of property, huge casualties, and many tragedies of broken families. Among them, family fires are more likely to cause fires and cause huge losses because of many risk factors that induce fires, low vigilance of personnel, lack of fire prevention and escape facilities, and inconvenient escape caused by high-rise or even super-high-rise buildings.

The home fire alarm controller can monitor the home environment at all times. When a fire occurs, the controller will immediately send out the sound and light indication signal of the fire alarm after receiving the fire alarm signal from the detector, which wins the victory for timely extinguishing the fire and personnel escape. Precious time can greatly reduce property damage and casualties.

In 2008, the country formulated and released the "Household Fire Safety System" standard, which has relevant regulations on the switching of main and backup power of household fire alarm controllers, detection of short circuit and open circuit faults of main and backup power, and protection of backup power. Regulation. Although the switching power supply of the traditional fire alarm controller has the functions of main and backup power switching, detection of short circuit and open circuit faults, and backup power protection, it usually uses relays as switching components, so it has slow action, noise, and voltage in the switching process. There are disadvantages such as drop, need to add additional compensation circuit, large volume, high cost and difficult to maintain.

Utility model content

Aiming at the shortcomings of the existing fire alarm controllers, such as slow switchover between main and backup power and noise, the utility model provides a fire alarm controller with automatic switching between main and backup power, a detection and protection circuit, which can realize automatic switching between main and backup power , MOS tube switching action is fast, and the switching process has the advantages of no noise.

The utility model adopts the following technical solutions:

A fire alarm controller main and backup power automatic switching, detection and protection circuit, including main and backup power automatic switching circuit, short-circuit open circuit detection circuit and backup power protection circuit;

The main and standby power automatic switching circuit includes the main power supply, lithium battery backup power supply, power switching chip and P-channel MOS tube, the main power supply is connected to the power switching chip, the power switching chip is connected to the P-channel MOS tube, and the power switching chip controls the P-channel The disconnection of the channel MOS tube, the backup power supply of the lithium battery is connected with the P channel MOS tube;

The short-circuit open circuit detection circuit includes a main power supply terminal voltage acquisition circuit and a lithium battery backup power supply terminal voltage acquisition circuit, the main power supply terminal voltage acquisition circuit is connected to the main power supply, and can collect the voltage of the main power supply, and the lithium battery backup power supply terminal voltage acquisition circuit Connected to the lithium battery backup power supply, it can collect the voltage of the lithium battery backup power supply;

The backup power protection circuit includes a lithium battery charging management chip, a diode and an N-channel MOS tube, the main power supply is connected to the lithium battery charging management chip through a diode, the lithium battery charging management chip is connected to the lithium battery backup power supply, and the main power supply can The lithium battery backup power is charged through the diode and the lithium battery charging management chip. The lithium battery charging management chip manages the power of the lithium battery backup power. When the lithium battery backup power is fully charged, the lithium battery charging management chip stops the main power supply to the lithium battery backup power. Charge;

The backup power supply of the lithium battery is connected with an N-channel MOS tube, and the N-channel MOS tube can be turned off when the backup power supply of the lithium battery is over-discharged.

Preferably, the positive pole of the main power supply is connected to the power switching chip and the diode respectively, the charging management chip of the lithium battery is connected to the positive pole of the backup power supply of the lithium battery, and the negative pole of the backup power supply of the lithium battery is connected to the main power supply through an N-channel MOS transistor. Negative connection.

Preferably, the main power supply terminal voltage acquisition circuit is connected to the positive and negative terminals of the main power supply, and the lithium battery backup power supply terminal voltage acquisition circuit is connected to the positive and negative terminals of the lithium battery backup power supply;

Both the main power supply terminal voltage acquisition circuit and the lithium battery backup power supply terminal voltage acquisition circuit include two resistors connected in series, and a capacitor is connected in parallel to one of the resistors.

Preferably, when the backup power supply of the lithium battery is discharging, if the power of the backup power supply of the lithium battery drops below the protection point, the N-channel MOS transistor is turned off.

The beneficial effect that the utility model has is:

The main and standby power automatic switching, detection and protection circuits of the fire alarm controller enable the fire alarm controller to realize automatic switching between the main power supply and the standby power supply, and during the switching process, other tasks of the fire alarm controller will not be caused The state change, and through the AD acquisition of the terminal voltage of the main power supply and the backup power supply, the detection of the failure of the main power supply and the backup power supply can be realized, and then the lithium battery backup power supply can be detected through the lithium battery charging management chip and the N-channel MOS tube. Overcharge and overdischarge protection. The utility model not only has small size, fast switching action, no noise in the switching process, no voltage drop, no additional compensation circuit, low cost of components, but also greatly improves the working stability, reliability and safety of the lithium battery backup power supply , In addition, due to the simple working principle, it is easy to troubleshoot, repair and maintain.

Description of drawings

Figure 1 is a circuit diagram of a fire alarm controller's main and backup power automatic switching, detection and protection circuits.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is specifically described:

Combined with Fig. 1, a fire alarm controller automatically switches main and backup power, detection and protection circuit, including main and backup power automatic switching circuit, short-circuit open circuit detection circuit and backup power protection circuit.

A main controller is also arranged in the fire alarm controller.

The main and backup power automatic switching circuit includes the main power supply, lithium battery backup power supply, power switching chip D1 and P-channel MOS tube V1, the main power supply is connected to the power switching chip D1, the power switching chip D1 is connected to the P-channel MOS tube V1, and the power supply The switching chip D1 controls the switching of the P-channel MOS transistor V1.

The backup power supply of the lithium battery is connected with the P-channel MOS transistor V1.

The short-circuit open circuit detection circuit includes a main power supply terminal voltage acquisition circuit and a lithium battery backup power supply terminal voltage acquisition circuit. The main power supply terminal voltage acquisition circuit is connected to the main power supply and can collect the voltage of the main power supply.

The lithium battery backup power supply terminal voltage acquisition circuit is connected to the lithium battery backup power supply, and can collect the voltage of the lithium battery backup power supply.

Both the main power supply terminal voltage acquisition circuit and the lithium battery backup power supply terminal voltage acquisition circuit are connected to the main controller.

The backup power protection circuit includes lithium battery charging management chip D2, diode V4 and N-channel MOS tube V5. The main power supply is connected to lithium battery charging management chip D2 through diode V4, and lithium battery charging management chip D2 is connected to lithium battery backup power supply. The power supply can charge the lithium battery backup power through the diode and the lithium battery charging management chip. The lithium battery charging management chip manages the power of the lithium battery backup power. When the lithium battery backup power is fully charged, the lithium battery charging management chip stops the main power supply from charging the lithium battery. Backup power for charging.

The backup power supply of the lithium battery is connected to the N-channel MOS transistor V5, and the N-channel MOS transistor V5 can be turned off when the backup power supply of the lithium battery is over-discharged.

Lithium battery charging management chip D2 and N-channel MOS transistor V5 are both connected to the main controller.

Specifically, the positive pole of the main power supply is connected to the power switching chip D1 and the diode V4 respectively, the lithium battery charging management chip D2 is connected to the positive pole of the lithium battery backup power supply, and the negative pole of the lithium battery backup power supply is connected to the main power supply through the N-channel MOS transistor V5. The negative poles are connected, and the negative pole of the main power supply is grounded.

The main power terminal voltage acquisition circuit is connected to the positive and negative terminals of the main power supply, and the lithium battery backup power supply terminal voltage acquisition circuit is connected to the positive and negative terminals of the lithium battery backup power supply;

Both the main power supply terminal voltage acquisition circuit and the lithium battery backup power supply terminal voltage acquisition circuit include two resistors in series, a capacitor is connected in parallel to one of the resistors, and the two resistors are connected to the main controller. The main controller can collect the main power supply. The voltage of the terminal and the voltage of the backup power supply terminal of the lithium battery.

As shown in Figure 1, the anode of the main power supply is connected to the SENSE pin of the power switching chip D1, the SENSE pin of the power switching chip is also connected to the source of the P-channel MOS tube, and the GATE pin of the power switching chip is connected to the P-channel The gate of the P-channel MOS transistor is connected, the VIN pin of the power switching chip is connected to the drain of the P-channel MOS transistor, and the GND pin and the CTL pin of the power switching chip are grounded.

The positive electrode of the lithium battery backup power is connected to the drain of the P-channel MOS tube, and the negative electrode of the lithium battery backup power is connected to the N-channel MOS tube.

The lithium battery backup power terminal voltage acquisition circuit includes resistors R1 and R2 connected in series, the resistor R1 is connected to the positive pole of the lithium battery backup power supply, the resistor R2 is connected to the negative pole of the lithium battery backup power supply, and a capacitor C2 is connected in parallel to the resistor R2.

The voltage acquisition circuit at the main power supply terminal includes resistors R11 and R12 connected in series, the resistor R11 is connected to the positive pole of the main power supply, the resistor R12 is connected to the negative pole of the main power supply, and a capacitor C6 is connected in parallel to the resistor R12.

The IN pin of the lithium battery charging management chip is connected to the negative pole of the diode V4, the negative pole of the diode V4 is grounded through the capacitor C5, the negative pole of the diode V4 is connected to the VBIAS pin of the lithium battery charging management chip through the resistor R7, and the lithium battery charging management chip’s The VBIAS pin is also grounded through the resistor R8, the negative pole of the diode V4 is connected to the ACOK pin of the lithium battery charging management chip through the series resistor R6 and the light-emitting diode V3, and the negative pole of the diode V4 is connected to the lithium battery through the series resistor R5 and the light-emitting diode V2 The CHG pin of the charging management chip is connected, the light-emitting diode V2 is the charging indicator light, and the light-emitting diode V3 is the power indicator light, which intuitively indicates the working status of the lithium battery charging management chip;

The EN pin of the lithium battery charging management chip is grounded through the resistor R10, connected to the DC 3.3V power supply through the resistor R9, the BATT pin of the lithium battery charging management chip is connected to the positive pole of the lithium battery backup power supply, and grounded through the capacitor C3; the lithium battery The ISET pin of the charging management chip is grounded through resistor R3, the IBF pin of the lithium battery charging management chip is grounded through resistor R4, the SS pin of the lithium battery charging management chip is grounded through capacitor C4, and the GND pin of the lithium battery charging management chip is grounded .

After the load is connected, a capacitor C1 is connected in parallel to the load. The main controller collects the voltage of the main power supply and lithium battery backup power supply at any time. When the main power supply is input, the power switching chip D1 controls the P-channel MOS transistor V1 to turn off. The main power supplies power to the load, that is, the current flows out through the positive pole of the main power supply, passes through the load, and then returns to the negative pole of the main power supply to form a power supply loop. At this time, the main power supply supplies power to the load; and when there is no main power input, the power switching chip D1 controls P The channel MOS tube is turned on. At this time, the backup power supply of the lithium battery is connected, and the current flows out through the positive electrode of the backup power supply of the lithium battery, passes through the P-channel MOS tube V1, passes through the load, and then passes through the N-channel MOS tube V5, and returns to the lithium battery backup power supply. The negative pole of the power supply forms a power supply circuit, that is, switches to the lithium battery backup power supply to supply power to the load. This realizes the automatic switchover of the main and backup power supplies. During this process, the power switch chip D1 detects whether the main power supply is input, and then controls the P-channel MOS transistor V1 to turn off and on.

When there is a main power supply and the lithium battery backup power supply is insufficient, the current flows out through the positive pole of the main power supply, passes through the diode V4, passes through the lithium battery charging management chip D2, reaches the positive pole of the lithium battery backup power supply, passes through the negative pole of the lithium battery backup power supply, and then passes through The N-channel MOS tube V5 returns to the negative pole of the main power supply to form a charging circuit; when the backup power of the lithium battery is fully charged, the lithium battery charging management chip D2 stops the main power supply to charge the backup power of the lithium battery, and realizes over-charging of the backup power of the lithium battery. charging protection function.

The main power supply terminal voltage acquisition circuit and the lithium battery backup power supply terminal voltage acquisition circuit can collect the main power supply terminal voltage and the lithium battery backup power supply terminal voltage value. Faults are detected to realize open circuit and short circuit detection.

When the lithium battery backup power supply is discharged, the current flows out through the positive electrode of the lithium battery backup power supply, passes through the P-channel MOS transistor V1, passes through the load, and then passes through the N-channel MOS transistor V5, and returns to the negative electrode of the lithium battery backup power supply. When the power is discharged below the protection point, the main controller controls the N-channel MOS tube V5 to turn off to realize the over-discharge protection of the lithium battery backup power supply.

Of course, the above description is not a limitation of the present utility model, and the present utility model is not limited to the above-mentioned examples, and changes, modifications, additions or replacements made by those skilled in the art within the essential scope of the present utility model are also acceptable. Should belong to the protection scope of the utility model.

Claims (4)

1. a kind of active and standby electric automatic switchover of fire alarm control unit, detection and protection circuit, which is characterized in that certainly including active and standby electricity Dynamic switching circuit, short interruption detection circuit and standby electric protection circuit；

Active and standby electricity automatic switch-over circuit includes main power source, lithium battery stand-by power supply, power supply switching chip and P-channel metal-oxide-semiconductor, main electricity Source is connected with power supply switching chip, and power supply switching chip is connected with P-channel metal-oxide-semiconductor, and power supply switches chip controls P-channel metal-oxide-semiconductor Cut-off, the lithium battery stand-by power supply is connected with P-channel metal-oxide-semiconductor；

The short interruption detection circuit includes main power source terminal voltage Acquisition Circuit and lithium battery standby electricity source voltage acquisition electricity Road, main power source terminal voltage Acquisition Circuit are connected on main power source, can acquire the voltage of main power source, lithium battery stand-by power supply terminal voltage Acquisition Circuit is connected on lithium battery stand-by power supply, can acquire the voltage of lithium battery stand-by power supply；

The standby electric protection circuit includes lithium battery charging management chip, diode and N-channel MOS pipe, and the main power source passes through Diode is connected with lithium battery charging management chip, and lithium battery charging management chip is connected with lithium battery stand-by power supply, main power source It can be charged for lithium battery stand-by power supply by diode and lithium battery charging management chip, lithium battery charging management chip manages lithium The electricity of battery backup power source, when lithium battery stand-by power supply is fully charged, lithium battery charging management chip stops main power source to lithium Battery backup power source charges；

The lithium battery stand-by power supply is connected with N-channel MOS pipe, and N-channel MOS pipe can be closed in lithium battery stand-by power supply overdischarge It is disconnected.

2. the active and standby electricity of a kind of fire alarm control unit according to claim 1 automatically switches, detects and protects circuit, special Sign is that the anode of the main power source switches chip with power supply respectively and diode is connected, the lithium battery charging management chip It is connected with the anode of lithium battery stand-by power supply, the cathode phase that the cathode of lithium battery stand-by power supply passes through N-channel MOS pipe and main power source Even.

3. the active and standby electricity of a kind of fire alarm control unit according to claim 1 automatically switches, detects and protects circuit, special Sign is that the main power source terminal voltage Acquisition Circuit is connected to the positive and negative end of main power source, lithium battery stand-by power supply terminal voltage Acquisition Circuit is connected to the positive and negative end of lithium battery stand-by power supply；

The main power source terminal voltage Acquisition Circuit and lithium battery standby electricity source voltage collection circuit include concatenated two electricity Resistance, a resistor in parallel has capacitance wherein.

4. the active and standby electricity of a kind of fire alarm control unit according to claim 1 automatically switches, detects and protects circuit, special Sign is, the lithium battery stand-by power supply in electric discharge, the electricity if lithium battery stand-by power supply put to protection point hereinafter, if N ditches Road metal-oxide-semiconductor shutdown.