RELAY DRIVER CIRCUIT
Power that is supplied to a primary coil of a transformer from a DC power supply that is connected to the primary coil is modulated based on continuous pulses supplied from a microcontroller, and power that is induced between terminals of a secondary coil of the transformer is supplied to a relay. A large driving current can be supplied to the relay thereby, thus making it possible to reduce the ripple component, and, as a result, to achieve stabilized operation.
1 . A relay driving circuit comprising:
a transformer;
a DC power supply connected to a primary coil of the transformer;
a modulating circuit for modulating, based on a control signal from the outside, voltage supplied to the primary coil of the transformer from the DC power supply; and
a supplying circuit for supplying power that is induced between the terminals of a secondary coil of the transformer to an electromagnetic relay that is provided with a mechanical contact point.
2 . A relay driving circuit as set forth in claim 1 , wherein:
the modulating circuit is structured from a switching element that is turned ON/OFF by a pulse signal, connected in series with the primary coil of the transformer and with the DC power supply.
3 . A relay driving circuit according to claim 1 , wherein:
the supplying circuit further comprises a rectifying circuit rectifying and supplying to the electromagnetic relay, power produced between the terminals of the secondary coil.