Electromagnetic coil drive device

• US 9,112,503 B2
• Filed: 08/02/2012
• Issued: 08/18/2015
• Est. Priority Date: 08/19/2011
• Status: Active Grant

• Current Assignee: Fuji Electric FA Components & Systems Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited), Fuji Electric FA Components & Systems Company Limited (Fuji Electric Systems Company Limited)
• Inventors: Morita, Akira, Taguchi, Takahiro
• Primary Examiner(s): Leja, Ronald W
• Application Number:
  US14/116,240
• Publication Number:
  US 20140092515A1
• Time in Patent Office: 1,111 Days
• Field of Search: 361/156
• US Class Current: 1/1
• CPC Class Codes: H01F 7/064 Circuit arrangements for actuating electromagnets circuit arrangements for obtaining special operating characteristics H01F7/18; driving circuits for electromagnets making use of a switching regulator H01H47/325
• CPC Class Codes: H03K 17/6877 the control circuit comprising active elements different from those used in the output circuit

Abstract

An electromagnetic coil drive device has a semiconductor switch connected in series with an electromagnetic coil for controlling a current supplied to the coil; a capacitor; a comparator for comparing a voltage to charge and discharge the capacitor with two different voltages, for generating a signal to operate on-off of the semiconductor switch in accordance with a result of a comparison; a first charging circuit to charge the capacitor based on a voltage applied to the coil; and a discharging circuit to discharge the capacitor. The first charging circuit has a first resistor and at least one compensating circuit connected in parallel with the first resistor; and a resistor and a Zener diode are connected in series in the compensating circuit.

Claims

1. An electromagnetic coil drive device, comprising:

a semiconductor switch connected in series with an electromagnetic coil for controlling a current supplied to the coil;

a capacitor;

a comparator for comparing a voltage to charge and discharge the capacitor with two different voltages, for generating a signal to operate on-off of the semiconductor switch in accordance with a result of a comparison;

a first charging circuit to charge the capacitor based on a voltage applied to the coil; and

a discharging circuit to discharge the capacitor;

wherein the first charging circuit has a first resistor and at least one compensating circuit connected in parallel with the first resistor, and

the compensating circuit includes;

a first compensating circuit in which a second resistor and a first Zener diode are connected in series, and

a second compensating circuit in which a third resistor and a second Zener diode are connected in series; and

the first Zener diode and the second Zener diode have different Zener voltages.

2. An electromagnetic coil drive device according to claim 1, further comprising a second charging circuit to charge the capacitor based on a stabilized voltage.

3. An electromagnetic coil drive device according to claim 1, wherein the first charging circuit further comprises a temperature sensing resistor element connected in series with the first resistor.

4. An electromagnetic coil drive device according to claim 3, wherein the temperature sensing resistor element has a positive temperature coefficient.