JPS5810337A - Relay drive circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a latching relay drive circuit.

When driving a latching relay with alternating current, it may not operate depending on the closing phase. The present invention seeks to provide a drive circuit that is operable in any closing phase.

FIG. 1 shows a conventional latching relay drive circuit. Conventionally, in the circuit shown in Fig. 1, when the operation switch 1 is turned on, the latching relay 2 is operated by the charging current of the capacitor, and when the operation switch is turned to the OFF side, the latching relay is reset by the discharging current of the capacitor. was.

FIG. 2(A) shows the capacitor voltage and the capacitor 11Y current when the switch is on, and FIG. 2(b) shows the capacitor voltage and current when the switch is off.

a is the half-wave rectified voltage, 1) is the capacitor voltage 11: , C
is the capacitor current, ■□ is the relay! J4 operating current, ■I indicates relay return current.

Figure 2 shows the characteristics when the closing phase is O, but when the operation switch is turned on, it is T. The input phase of is random, and if the input phase is not 0, it is shown in Fig. 3a.

As shown in b, the capacitor charge flow may not reach the operating current of the relay, and the relay may not operate ml1. The present invention aims to improve the above-mentioned drawbacks and provide a drive circuit that enables operation regardless of when the operating switch is turned on.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 4 shows an embodiment of the present invention, in which one terminal p of the AC power supply 11 is connected to the on-side terminal of the operation switch 12, to the transistor Tr, to the capacitor C, and to the relay coil 13 via the diode D1. is connected to the other terminal q of the AC power supply 11, the pace of the transistor Tr is connected to the terminal qKM' of the AC power supply 11 via the capacitor C2, and both ends of the capacitor C2 are connected to the other terminal q of the AC power supply 11. A closed circuit is formed through the secondary winding of the transformer 14, and one end of the primary winding of the transformer 14 is connected to the connection point between the on-side terminal 12b of the operation switch 12 and the diode D, and the other end is connected to terminal q of AC power supply 11. Also, the connection point between the emitter of the transistor Tr and the capacitor CI is
)"D2. Off-side terminal 12d of operation switch 12,
12c is connected to terminal q of the AC power source via a resistor R.

The NAO transformer 14 is a transformer for phase shift conversion.

Next, the operation of the present invention will be explained.

Considering a state where terminal p is positive and terminal q is negative in the voltage waveform of AC power supply 11, the current changes from p→12a
→12'b→D1→Tr Since the transistor Tr is in the off state at the collector, no current flows.

Next, it flows as p → 12a → 12b → primary side of transformer 14 → q. On the primary side of the transformer, current flows in the direction of the solid line arrow, but since this transformer is a phase inversion transformer, on the secondary side of the transformer, current flows in the direction of the solid line arrow, but the diode D , so no current flows.

Next, the polarity of the AC power supply is reversed and the side terminal becomes +.

When the p terminal becomes -, a current flows in the direction opposite to the arrow on the primary side of the transformer 14, and as a result, a current flows on the secondary side of the transformer in the direction opposite to the direction of the solid arrow, that is, the direction shown by the broken line. Since the capacitor C2 is charged to the polarity shown, the transistor Tr becomes conductive.

Next, when the polarity of the AC power source changes again and the p terminal becomes t and the side terminal becomes -, the transistor Tr is turned on, so the current is a-+ l 2a-+ l 2cm+ D, -+ T
The flow is r-*Q, -+ l 3-+ b, and the relay is activated.

When the operation switch SW is turned off, the current in the capacitor CI flows through C1→D2→12d→12cm+R→13, so the relay returns to its original state.

FIG. 5 shows the current and voltage waveforms of various parts when the switch is turned on.

When the operation switch is turned on as described above, the circuit of the present invention starts operating at the zero point of the second half wave, as shown in FIG. 5, regardless of the input phase. Also, when the operation switch is turned off, the relay returns to normal operation due to the discharge current of the capacitor, similar to the conventional circuit.

FIG. 6 shows another embodiment of the present invention, and FIG. 7 shows waveforms at various parts. According to the present invention, the primary side of the phase inverting transformer is connected to an AC power supply via an operation switch, a capacitor is connected to the secondary side of the phase inverting transformer, and the charging voltage of the capacitor is applied to the base of the transistor. (5) By configuring it so that it is applied to It has the effect of operating the relay even if it is turned on.

[Brief explanation of the drawings] Figure 1 shows a conventional relay drive circuit, a of Figure 2 (a),
b, c, (b), c and Fig. 3 a, 'b, c are waveforms of each part, Fig. 4 is an embodiment of the present invention, Fig. 5 half-wave rectified voltage to capacitor C, current is each part. FIG. 6 shows another embodiment of the present invention. Figure 7 Power supply voltage - Capacitor 0.
'^ The flow shows the waveform of each part. 12... Operation switch, 13... Relay coil, 1
4... Phase inversion transformer, p, q... AC power supply terminal, D1-D,... diode, Tr... transistor, C8°C2... capacitor, R... resistor Patent applicant (6) Figure 1...l:r;2 Figure 4 2 Figure 5

Claims (1)

[Claims] A series circuit including a diode, a collector and an emitter of a transistor, a first capacitor, and a relay coil are connected to both terminals of an AC power source through an ON terminal of the operation switch, and a circuit in which a series circuit of a diode, a collector and an emitter of a transistor, a first capacitor, and a relay coil are connected to both terminals of an AC power supply through an ON terminal of the operation switch; 1 a closed circuit that connects a capacitor, a relay coil, and a resistor; a circuit that connects the primary side of a phase inverting transformer to both terminals of the AC power supply via the on contact of the operation switch; 1. A relay drive circuit comprising: a second capacitor connected to the secondary side of a phase inversion transformer; and a circuit through which a charging voltage of the capacitor is applied to the base of the transistor.