Ac line powered relay driving circuits
AssigneeEmerson Electric Co.
InventorsCuiyun Chen, Xingeng Zhou
Life of this patent
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Abstract
Disclosed are exemplary embodiments of relay drive circuits. In an exemplary embodiment, a relay drive circuit generally includes a first diode, a second diode, a third diode, a first transistor, a second transistor, a first capacitor, and a second capacitor. The relay drive circuit is operable to transform an AC voltage to a DC voltage, and then use the DC voltage to control on/off of the relay.
Claims15
A relay drive circuit comprising:
- a first diode having a positive pole and a negative pole;
- a first capacitor having a positive pole and a negative pole;
- a first transistor having a base, an emitter, and a collector;
- and
- an integrated circuit configured to transform high voltage DC current into low voltage DC current, the integrated circuit including a first terminal, a second terminal, and a third terminal;
- wherein:
- the positive pole of the first diode is electrically connected to a positive terminal of an AC supply;
- the negative pole of the first diode is electrically connected to the positive pole of the first capacitor;
- the negative pole of the first capacitor is connected to a negative terminal of the AC supply;
- the base of the first transistor is connected with a drive signal;
- the collector of the first transistor is connected with a relay;
- the emitter of the first transistor is connected to the negative pole of the first capacitor;
- the first terminal of the integrated circuit is connected to the negative pole of the first diode and the positive pole of the first capacitor;
- the second terminal of the integrated circuit is connected to the relay;
- and
- the third terminal of the integrated circuit is connected to the negative pole of the first capacitor.
An AC line powered relay driving circuit operable for using AC line voltage directly to provide power to drive a relay, the relay drive circuit comprising:
- a rectifying circuit electrically connected with an AC power supply to rectify high AC voltage into high DC voltage;
- a DC voltage converting circuit electrically connected between the rectifying circuit and the relay, the DC voltage converting circuit operable to transform high DC voltage into low DC voltage;
- and
- a capacitor in parallel with the relay such that voltage on the capacitor turns on the relay, wherein voltage on the capacitor is controllable by a duty cycle and frequency of a drive signal.
A method of using AC line voltage directly to provide power to drive a relay, the method comprising:
- rectifying high AC voltage into high DC voltage;
- transforming high DC voltage into low DC voltage;
- and
- controlling a charge on a capacitor in parallel with the relay by a duty cycle and frequency of a drive signal, whereby low DC voltage on the capacitor in parallel with the relay turns on the relay.
Dependencies are inferred from the claim text.