JPH0261930A - Relay drive circuit - Google Patents

Abstract

PURPOSE:To enable low voltage driving by providing a capacitor supplying power source to a set coil and a reset coil in a set circuit and a reset circuit respectively. CONSTITUTION:A relay drive circuit is composed of the set circuit 1 exciting a set coil 3 and the reset circuit 2 exciting a reset coil 4. A capacitor C1 is provided in the circuit 1 and a capacitor C2 in the circuit 2 respectively for power source. By the way, the changing of the ratio between resistance R2 and R3 enables working voltage to be controlled and that between R11 and R12 enables open voltage to be controlled. The changing of the capacitors C1 and C2 enables the lowering of relay set and reset drive pulse voltage to be controlled. Since the electric power at the time of setting and that at the time of resetting are covered with the capacitors C1 and C2 respectively and divided individually in this constitution, the working voltage and the open voltage can be made to below 3V.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a relay drive circuit that drives a relay using battery power.

[Prior Art J] Figure 4 shows a conventional relay drive circuit, including a set circuit 1' that excites the set fill 3 of the relay and a reset coil 4.
The reset circuit 2' etc. which energizes the terminal C and the ground terminal G.
A capacitor C0 is connected between them for power supply. In addition, to the output terminal S of the set circuit 1',
The sector fill 3 of the relay is connected, and the power supply side of the set coil 3 is connected to the terminal C. A reset coil 4 is connected to the output terminal R of the reset circuit 2', and the power supply side of the reset coil 4 is also connected to the terminal C. The set circuit 1' includes transistors Tr, -Tr5
, resistors R1-RIZ, capacitor C0, etc. The reset circuit 2' includes transistors Tr6 to Tr.
1, resistors R1, l-, etc.

The operation of this circuit is as follows. Incidentally, since the operation is basically the same as that of the embodiment described later, the details will be described in the embodiment, and a relatively simple explanation will be given here. When power is applied to the terminal Vin, the capacitor C0 is charged. On the other hand, the transistor Tr is not turned on immediately due to the set values of the resistors R2 and R31Rs-Rt, and the transistor Tr2 is turned on before the transistor Tr is turned on after the N source is applied. Therefore, the collector of transistor Trz is at L level, but when transistor Tr is turned on, transistor T2 is turned off and the collector of transistor Tr2 is at H level, but the base of transistor Tr3 is connected to resistor R3 and capacitor C1. Therefore, since the collector of transistor Tr3 is at H level from when transistor Trt is turned off until transistor Tr3 is turned on, transistors Tr, Tr5 are turned on during this time. The set coil 3 is excited by the resistor R9 and the capacitor C5.The pulse width for driving the set coil 3 of the relay can be controlled by this resistor R9 and the capacitor C5.

Next, the case where the reset coil 4 is excited will be explained. When the power is removed, the transistor Tr is turned off,
By turning on the transistor Tr6, the transistor T
rs is off, transistor T'.+T'rl+ is on, and the reset coil 4 is excited.

The power source at this time is the charge from the capacitor C0, and the reset coil 4 is excited until the capacitor C0 is no longer charged.

[Problem to be Solved by the Invention] In the above circuit, 5 µ is used as the power supply voltage, but if it is driven at a low voltage of 3 µ, for example, the circuit shown in Fig. 4 cannot be operated. First, in order to operate, one external capacitor C0 must drive both the set and reset coils.
There is a problem in that the capacitance of capacitor C8 must be made very large. Further, since the inrush current is large, a separate power supply is required, and there is a problem in that the device cannot be operated at the TTL level. In addition, in the past, a resistor R for driving the base of the transistor Tr3
If the values of 5 and capacitor C1 are not set strictly, there will be problems such as oscillation or failure to reset when the circuit is turned off immediately after being set.

The present invention has been provided in view of the above-mentioned points, and provides a relay drive circuit that is intended to operate even with a power supply voltage as low as 3V.

[Means for Solving Problem 1111] According to the present invention, capacitors for supplying power to the set coil and reset coil are provided in the set circuit and the reset circuit, respectively.

[Function] Excitation of the set coil in the set circuit and excitation of the reset coil in the reset circuit are performed by separate capacitors, respectively.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. It is composed of a set circuit 1 that excites a set coil 3 and a reset circuit 2 that excites a reset coil 4 as in the conventional case. The set circuit 1 includes a transistor T r+ −T
rs, resistors Rz-Rlo, capacitor C4, etc., and a capacitor C1 is provided as a power source for the set circuit 1. Further, the reset circuit 2 includes a trannostar T
r, -Tr1, etc., and a capacitor C2 is provided as a power supply. Note that by changing the ratio between resistors R2 and R2, the impression voltage can be controlled, and by changing the ratio between resistors R11 and R12, the open circuit voltage can be controlled. Furthermore, by changing the resistor R5, the inrush current can be controlled (several mA or so), by changing the capacitor C5 or the resistor R, the relay set drive pulse width can be controlled, and by changing the capacitors C, , C, , it is possible to control the voltage drop of the relay set and reset drive pulses, and therefore, these relay drive pulses can be controlled.
Can operate various types of latching relays. In addition, the power for setting is provided by capacitor C, and the power for resetting is provided by capacitor C2, and the power is divided between each, so I am impressed as will be described later.

The open circuit voltage can be reduced to 3V or less.

Next, the operation will be explained. First, in the set operation, as shown in FIG. 2(a), the voltage Vl on the positive electrode side of the capacitor C1 starts to be supplied from the power supply Vcc from time t0, and the voltage Vl on the positive side of the capacitor C1 slowly increases. increases, and current flows through the set coil 3 between times t1 and t2, so the charge in the capacitor C is discharged and the voltage drops. In addition, time 1. is the time when the transistor Tr is turned on and the transistor Tr2 is turned off. Even if the power supply VCC is supplied, set values of the resistors R2 to R, , R, etc. are set so that the transistor Trl does not turn on, and a voltage is set between the base and emitter of the transistor Tr that turns on at time t. so that it is applied. Therefore,
Since the transistor Tr+ is turned on at the time, the same figure (
As shown in b), at time 11, the transistor T
r2 turns on, and the voltage V at the collector of transistor Trz
, is at L level, and becomes H level from time t when transistor Trl is turned on and transistor Tr2 is turned off, thereafter.

As shown in the figure (e), the transistor T
Since r2 is turned on, the voltage V31 is at the thick level, and at time t, when the voltage at the base of the transistor Tr= is at the V+M L level, the transistor Tr2 is turned off, so the voltage ■ is at the H level, but the voltage V, rises slowly due to resistor R6 and capacitor C5. From time t,■
, becomes L level, current flows through resistor R3 and diode D, and ■.

becomes L level, as shown in FIG. 3(d). At time t, ■ becomes H level ((b) in the same figure), but (C) in the same figure
As shown in FIG.
Q). After that, transistor Tr3 turns on at t288.
-, resistor R, transistor Tr3, resistor R.

. A current flows through, and Vs becomes L level ((d) in the same figure).
.

■While T is at H level (tl - tz), transistor T
r.

Tr5 is turned on, voltage 6 at the collector of transistor Tr5 becomes L level as shown in FIG. 2(e), current flows through set coil 3, and the relay is set. The coil power consumption is supplied from capacitor C0.

Next, the reset operation will be explained. ! @Figure 3 (a)
As shown in FIG. 2, at time t when the power supply Vcc is removed, the base voltage (2) of the transistor Tr6 becomes L level. When (2) becomes L level, the transistor Tr6 is turned off, and the collector voltage (2)8 becomes H level as shown in FIG. 2(b). ■When the voltage reaches H level 1, the transistor TratTr@ turns on, and the voltage V at the collector of the transistor Trs becomes L level as shown in the same figure (C), and the current flows through the reset fill 4 until the capacitor C2 is completely discharged. The relay will reset.

In this way, the capacitor C is used for setting and resetting.
By dividing the power supply between I and 02, it is possible to operate with a power supply voltage of 3V.

[Effect of the Invention J] As described above, the present invention is provided with capacitors for supplying power to the set fill and reset coils in the set circuit and the reset circuit, respectively, so that the excitation of the set coil in the set circuit, By energizing the reset coils in the reset circuit with separate capacitors, it is possible to drive at a low voltage of, for example, 3μ, and it is also possible to reduce the sudden rush current at the initial stage of use, making it possible to
It can operate at the L level and has the effect of reducing power consumption. Furthermore, the working voltage in the United States (
5), it can be used stably over a wide range of temperatures, and can operate stably especially at high temperatures even if there are variations in the constants of the electronic components.

[Brief explanation of the drawing]

Fig. 1 is a specific circuit diagram of an embodiment of the present invention, Fig. 2 is an operating waveform diagram when setting the same as above, Fig. 3 is an operating waveform diagram when resetting the same as above, and Fig. 4 is a specific circuit diagram of a conventional example. It is. 1 is a set circuit, 2 is a reset circuit, 3 is a set coil, 4 is a reset coil, and C, , C, are capacitors. Agent Patent Attorney Ishi 1) 艮 7th figure 2? + Figure 3

Claims (1)

[Claims] (1) In a relay drive circuit equipped with a set circuit that excites the set coil of the relay after power is applied, and a reset circuit that excites the reset coil of the relay after the power is removed, the set coil and reset coil are A relay drive circuit characterized in that a capacitor for supplying power is provided in each of the set circuit and the reset circuit.