JP2010110063A - Voltage control circuit and electric lock device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an overcurrent preventing circuit 11 that determines whether an overcurrent will flow through an electric lock control circuit 2 before the overcurrent actually flows through the electric lock control circuit 2. <P>SOLUTION: A voltage dividing resistor Rs 6 is connected in series with a power source 9a and the electric lock control circuit 2 to divide supply voltage. When a cable 4 is short-circuited, approximately 0V is detected as divided voltage applied to the electric rock control circuit 2 by an AD converter 7. When the divided voltage is not approximately 0V, CPU 1 determines that the cable 4 is not short-circuited and controls a relay circuit Ry 8 to short circuit the voltage dividing resistor Rs 6. As a result, rated voltage is applied to an electric rock circuit 12 and an electric rock 3 is released. When the divided voltage is approximately 0V, the CPU 1 determines that the cable 4 is short-circuited and controls the relay circuit Ry 8 not to short circuit the voltage dividing resistor Rs 6. Owing to the division of supply voltage by the voltage dividing resistor Rs 6, an overcurrent flows through the electric rock control circuit 2 even if the cable 4 is short-circuited. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a voltage control circuit and an electric lock device that constitute an electric lock control panel that is installed near a door and locks and unlocks the electric lock of the door, for example.

Patent Document 1 discloses an overcurrent prevention unit that includes an overcurrent detection unit that detects that an overcurrent has passed through a load circuit, and a voltage control unit that converts the level of a power supply voltage and supplies a constant output voltage to the load circuit. A circuit is disclosed.
JP 2005-333736 A

  In the technique disclosed in Patent Document 1, since voltage control is performed after an overcurrent flows through the load circuit, the load circuit may break down due to the overcurrent flowing before the voltage control is performed. There is a problem.

  An object of the present invention is to provide a circuit for determining in advance whether or not an overcurrent flows through a load circuit before the overcurrent flows through the load circuit.

  The voltage control circuit of the present invention is a voltage control circuit that controls a voltage applied to the electric circuit by connecting to a power supply and a specific electric circuit, and the voltage of the power supply is applied to the voltage applied to the electric circuit and the electric circuit. A power supply voltage dividing unit that divides the voltage into an unapplied voltage; a divided voltage measuring unit that measures a voltage applied to the electric circuit divided by the power supply voltage dividing unit as a divided voltage; and the divided voltage measuring unit A short-circuit detecting unit for detecting a short circuit of the electric circuit based on the divided voltage measured by the voltage dividing unit by the power source voltage dividing unit when the short circuit detecting unit does not detect a short circuit of the electric circuit. A voltage dividing control unit that stops and supplies the voltage of the power source to the electric circuit.

  ADVANTAGE OF THE INVENTION According to this invention, the circuit (voltage control circuit) which determines beforehand whether overcurrent flows into a load circuit before overcurrent flows into a load circuit (electric circuit) can be provided, for example.

Embodiment 1 FIG.
An overcurrent prevention circuit that is connected to a power source and a specific electric circuit (for example, an electric lock circuit) to control a voltage applied to the electric circuit and prevents an overcurrent from flowing through the electric circuit will be described.

FIG. 1 is a configuration diagram of an electric lock device 10 according to the first embodiment.
The configuration of the electric lock device 10 having the overcurrent prevention circuit 11 in the first embodiment will be described below with reference to FIG.

  The electric lock device 10 includes an electric lock circuit 12 that locks and unlocks the electric lock 3, an overcurrent prevention circuit 11 that detects a short circuit in the electric lock circuit 12 and prevents an overcurrent from flowing through the electric lock circuit 12, Have

The electric lock circuit 12 includes an electric lock 3 (an example of the second circuit) and an electric lock control circuit 2 (an example of the first circuit) that controls the electric lock 3, and the electric lock 3 and the electric lock control circuit 2. Are connected by a cable 4.
The electric lock 3 incorporates a drive mechanism (electric circuit) such as a motor (M) and a solenoid (coil), and the electric lock control circuit 2 incorporates transistor switches (FETs) (Tr_a to Tr_d).
When the electric lock 3 is unlocked, an electric signal is output from the CPU 1 to the electric lock control circuit 2, the transistor switches (Tr_a to Tr_d) are energized, and the power (voltage, current) of the power source 9a is changed to the electric lock control circuit 2. From the transistor switch to the electric lock 3 via the cable 4.
The electric lock 3 to which the power is supplied is locked and unlocked by operating the drive mechanism.

  The overcurrent prevention circuit 11 includes a voltage dividing resistor Rs6 (an example of a power supply voltage dividing unit), an AD converter 7 (an example of a divided voltage measuring unit), a CPU 1 (an example of a short circuit detecting unit), and a relay circuit Ry8 (a voltage dividing control). Part of an example). For the sake of simplicity, FIG. 1 shows that one relay circuit Ry8 is divided into two parts, the upper side of the voltage dividing resistor Rs6 and the right side of PortD of the CPU1.

The voltage dividing resistor Rs6 is connected in series with the power source 9a and the electric lock control circuit 2.
When the electric lock 3 is locked and unlocked, the voltage dividing resistor Rs6 is short-circuited between the power supply 9a side and the electric lock circuit 12 side by the relay circuit Ry8. Before the electric lock 3 is unlocked, the short circuit of the voltage dividing resistor Rs6 by the relay circuit Ry8 is released.

Before the unlocking of the electric lock 3 to be released from the short circuit, the voltage dividing resistor Rs6 divides the voltage of the power source 9a into the voltage applied to itself and the voltage applied to the electric lock circuit 12. The voltage of the power source 9a is divided by the ratio between the resistance value of the voltage dividing resistor Rs6 and the value of the internal resistance of the electric lock circuit 12. If the ratio of the resistance value of the voltage dividing resistor Rs6 is large, a voltage larger than that of the electric lock circuit 12 is applied to the voltage dividing resistor Rs6 by that ratio, and a voltage smaller than the voltage dividing resistor Rs6 is applied to the electric lock circuit 12 by that ratio. . The voltage dividing resistor Rs6 makes the current flowing through the electric lock circuit 12 a minute current.
For example, a resistor having a magnitude equal to or greater than the internal resistance of the electric lock 3 (drive mechanism resistance) is used as the voltage dividing resistor Rs6.
At the time of locking / unlocking the electric lock 3 in which the voltage dividing resistor Rs6 is short-circuited, the power supply voltage is not divided.

When there is a short circuit in the electric lock circuit 12, the internal resistance value of the electric lock circuit 12 becomes small. Therefore, the voltage applied to the electric lock circuit 12 among the power supply voltages divided by the voltage dividing resistor Rs6 (hereinafter referred to as “divided voltage”). Voltage)) becomes smaller. For example, when the cable 4 connecting the electric lock control circuit 2 and the electric lock 3 is short-circuited, the resistance of the electric lock 3 is not applied to the electric lock circuit 12, so that the resistance value of the electric lock control circuit 2 is the electric lock. The internal resistance value of the circuit 12 is obtained, and the divided voltage applied to the electric lock circuit 12 is substantially “0V”. Here, it is assumed that the resistance value of the electric lock control circuit 2 is sufficiently smaller than the resistance value of the electric lock 3 and the resistance value of the voltage dividing resistor Rs6.
For example, when the resistance value of the voltage dividing resistor Rs6 is about the same (or higher) as the internal resistance value of the electric lock 3, the voltage of the power source 9a is divided before being applied to the electric lock control circuit 2. Due to the resistor Rs6, the voltage drops about the same as (or more than) the voltage applied to the electric lock 3 during unlocking. For this reason, even if the cable 4 is short-circuited, the divided voltage applied to the electric lock control circuit 2 is less than the rated voltage of the electric lock control circuit 2 and the magnitude of the current flowing through the electric lock control circuit 2 is less than the rated current. Become. That is, even if the cable 4 is short-circuited, no overcurrent flows through the electric lock control circuit 2, and the electric lock control circuit 2 does not fail. Since the current flowing through the electric lock circuit 12 is a minute current, the electric lock control circuit 2 does not fail.

The AD converter 7 has an input side connected between the voltage dividing resistor Rs6 and the electric lock control circuit 2 and an output side connected to the PortC of the CPU 1, and measures a divided voltage applied to the electric lock circuit 12.
Specifically, the AD converter 7 inputs the divided voltage applied to the electric lock circuit 12 as an analog signal, acquires the value of the divided voltage from the input analog signal, and digitally converts the acquired value of the divided voltage. It converts into a value and outputs it to PortC of CPU1.

The CPU 1 has Port A and Port B connected to the transistor switches (Tr_a to Tr_d) of the electric lock control circuit 2.
Further, the CPU 1 has PortC connected to the AD converter 7, PortD connected to the transistor switch (Tr_e) for operating the relay circuit Ry8, and PortE connected to the LED 13.

  When the CPU 1 locks and unlocks the electric lock 3, first, the CPU 1 outputs an electric signal from the Port D to energize the transistor switch Tr_e. When the transistor switch Tr_e is energized, the relay circuit Ry8 operates (OFF) and the short circuit of the voltage dividing resistor Rs6 is released. Next, the CPU 1 starts outputting electric signals from the Port A and the Port B to the electric lock control circuit 2. Each transistor switch (Tr_a to Tr_d) is energized by the output of an electric signal to the electric lock control circuit 2, and a divided voltage is applied to the electric lock circuit 12. The voltage value (digital value) is input to PortC.

When the digital value of the divided voltage is input from the AD converter 7 to the PortC, the CPU 1 has a digital value of the divided voltage and a predetermined value (for example, a value lower than the rated voltage of the electric lock control circuit 2 and close to “0V”). To determine whether or not the electric lock circuit 12 (in particular, the cable 4) is short-circuited.
The CPU 1 determines that the electric lock circuit 12 is short-circuited when the divided voltage value is equal to or less than a predetermined value, and determines that the electric lock circuit 12 is not short-circuited when the divided voltage value is greater than the predetermined value. To do.

When the electric lock circuit 12 is short-circuited, the CPU 1 turns on (or blinks or turns off) the LED 13 connected to Port E to notify the short circuit failure of the electric lock circuit 12. And CPU1 complete | finishes the output of the electrical signal from PortA and PortB. At this time, the electric lock 3 is not locked / unlocked.
When the electric lock circuit 12 is not short-circuited, the CPU 1 outputs an electric signal from PortD to energize the transistor switch Tr_e. By energizing the transistor switch Tr_e, the relay circuit Ry8 operates (ON), the voltage dividing resistor Rs6 is short-circuited, and the voltage dividing of the power supply voltage by the voltage dividing resistor Rs6 is stopped. At this time, since voltage division by the voltage dividing resistor Rs6 is not performed, the rated voltage is applied to the electric lock circuit 12, the drive mechanism of the electric lock 3 operates, and the electric lock 3 is locked and unlocked. After locking and unlocking the electric lock 3, the CPU 1 ends the output of electric signals from Port A and Port B.

  The CPU 1 determines whether the electric lock circuit 12 is short-circuited by turning off the relay circuit Ry8 before locking and unlocking the electric lock 3, and turns on the relay circuit Ry8 when determining that the electric lock circuit 12 is not short-circuited. Thus, the two-stage control for locking and unlocking the electric lock 3 is performed.

  The relay circuit Ry8 is connected to the power source 9b, and is turned ON / OFF by energization of the transistor switch Tr_e by the CPU1. The relay circuit Ry8 directly connects the power supply 9a side of the voltage dividing resistor Rs6 and the electric lock circuit 12 side of the voltage dividing resistor Rs6 when the relay circuit Ry8 is ON, and shorts the voltage dividing resistor Rs6. The direct connection between the voltage dividing resistor Rs6 and the electric lock circuit 12 is removed, and the short circuit of the voltage dividing resistor Rs6 is released.

In the first embodiment, the following electric lock device 10 has been described.
When the electric lock 3 is controlled, the overcurrent prevention circuit 11 of the electric lock control panel that locks and unlocks the electric lock 3 of the door detects a short circuit of the cable 4 connected to the electric lock 3 so that no overcurrent flows. The electric lock control circuit 2 is protected.
The overcurrent prevention circuit 11 detects a short circuit of the cable 4 connecting the electric lock control circuit 2 and the electric lock 3 by measuring the divided voltage of the electric lock circuit 12 generated by the minute current loop.
The overcurrent prevention circuit 11 is rated by passing a minute current between the electric lock control circuit 2 and the electric lock 3 even when the cable 4 connecting the electric lock control circuit 2 and the electric lock 3 is short-circuited. The short circuit of the cable 4 can be easily confirmed before applying the voltage (rated current), and the electric lock control circuit 2 can be easily prevented from being damaged or damaged by the short circuit current (overcurrent).

Embodiment 2. FIG.
An electric lock device comprising a circuit that detects whether or not an overcurrent flows in the electric lock control circuit 2 and stops supplying the current to the electric lock control circuit 2 when it is detected that an overcurrent flows in the electric lock control circuit 2 10 will be described.
Hereinafter, description of items described in the first embodiment will be omitted.

FIG. 2 is a configuration diagram of the electric lock device 10 according to the second embodiment.
The electric lock device 10 according to the second embodiment includes an overcurrent detection and current stop circuit 5 in addition to the configuration described in the first embodiment.

  The overcurrent detection and current stop circuit 5 is connected to the power source 9a and the voltage dividing resistor Rs6, detects whether an overcurrent flows in the electric lock control circuit 2, and detects that an overcurrent flows in the electric lock control circuit 2. In this case, the supply of current to the electric lock control circuit 2 is stopped.

FIG. 3 is a configuration diagram of the overcurrent detection and current stop circuit 5 according to the second embodiment.
The configuration of the overcurrent detection and current stop circuit 5 in the second embodiment will be described below with reference to FIG.

  The overcurrent detection and current stop circuit 5 includes an overcurrent detection circuit 21 that detects whether an overcurrent has flowed through the electric lock control circuit 2, and an electric lock when it is detected that an overcurrent has flowed through the electric lock control circuit 2. And a current stop circuit 22 for stopping current supply to the control circuit 2.

  The current stop circuit 22 includes a transistor switch Tr_f. When the transistor switch Tr_f is energized, a current is supplied to the electric lock control circuit 2.

The overcurrent detection circuit 21 includes a resistor Re connected in series to the power source 9a and the electric lock control circuit 2 via a voltage dividing resistor Rs6 and a current stop circuit 22.
Further, the overcurrent detection circuit 21 includes a comparator Cmp that outputs a current to the transistor switch Tr_f of the current stop circuit 22 and energizes the transistor switch Tr_f when a voltage less than a predetermined value is applied to the resistor Re. When a voltage higher than a predetermined value is applied to the resistor Re, no current is output from the comparator Cmp to the transistor switch Tr_f.

  When the cable 4 is short-circuited, since the internal resistance of the electric lock 3 is not applied, a large voltage is applied to the resistance Re of the overcurrent detection circuit 21. When a large voltage is applied to the resistor Re, no current is output from the comparator Cmp to the transistor switch Tr_f, so that the transistor switch Tr_f is not energized and the supply of current to the electric lock control circuit 2 is stopped.

  By adding the overcurrent detection and current stop circuit 5, it is possible to prevent the overcurrent from flowing through the electric lock control circuit 2.

FIG. 4 is another configuration diagram of the electric lock device 10 according to the second embodiment.
As shown in FIG. 4, a plurality of electric lock circuits 12 may be controlled.

1 is a configuration diagram of an electric lock device 10 according to Embodiment 1. FIG. The block diagram of the electric lock apparatus 10 in Embodiment 2. FIG. FIG. 6 is a configuration diagram of an overcurrent detection and current stop circuit 5 in the second embodiment. FIG. 6 is another configuration diagram of the electric lock device 10 according to the second embodiment.

Explanation of symbols

  1 CPU, 2 electric lock control circuit, 3 electric lock, 4 cable, 5 overcurrent detection and current stop circuit, 6 voltage dividing resistor Rs, 7 AD converter, 8 relay circuit Ry, 9a, 9b power supply, 10 electric lock device, 11 Overcurrent prevention circuit, 12 Electric lock circuit, 13 LED, 21 Overcurrent detection circuit, 22 Current stop circuit.

Claims (6)

A voltage control circuit for connecting a power source and a specific electric circuit to control a voltage applied to the electric circuit;
A power supply voltage divider for dividing the voltage of the power supply into a voltage applied to the electric circuit and a voltage not applied to the electric circuit;
A divided voltage measuring unit that measures a voltage applied to the electric circuit divided by the power supply voltage dividing unit as a divided voltage;
A short-circuit detection unit that detects a short circuit of the electric circuit based on the divided voltage measured by the divided voltage measurement unit;
A voltage dividing control unit that stops voltage division by the power supply voltage dividing unit and supplies the voltage of the power supply to the electric circuit when a short circuit of the electric circuit is not detected by the short circuit detecting unit. A characteristic voltage control circuit. The power source voltage dividing unit has a resistor connected in series between the power source and the electric circuit as a voltage dividing resistor,
2. The voltage dividing control unit according to claim 1, wherein the voltage dividing unit stops the voltage dividing by the power supply voltage dividing unit by short-circuiting the power supply side of the voltage dividing resistor and the electric circuit side of the voltage dividing resistor. Voltage control circuit. The voltage control circuit according to claim 1, wherein the short-circuit detection unit determines that the electric circuit is short-circuited when the divided voltage is equal to or lower than a predetermined value. The divided voltage measurement unit includes an AD converter that inputs the divided voltage as an analog value, converts the analog value of the input divided voltage into a digital value, and outputs the digital value of the divided voltage. ,
The said short circuit detection part has CPU (Central Processing Unit) which detects the short circuit of the said electric circuit based on the digital value of the said divided voltage output by the said divided voltage measurement part. -Voltage control circuit in any one of the electric lock 3. The electrical circuit has a first circuit, a second circuit, and a connection cable for connecting the first circuit and the second circuit,
The power supply voltage dividing unit is located between the power supply and the first circuit and divides the voltage of the power supply. When the connection cable is short-circuited, an overcurrent is generated in the first circuit. The voltage control circuit according to claim 1, wherein the voltage control circuit prevents flow. A voltage control circuit according to claim 5 and an electric circuit according to claim 5,
The second circuit is an electric lock circuit for locking and unlocking the electric lock;
The electric lock device, wherein the first circuit is an electric lock control circuit for controlling the electric lock circuit.

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