ELECTROMAGNETIC COIL DRIVE DEVICE

• US 20140092515A1
• Filed: 08/02/2012
• Published: 04/03/2014
• 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: Taguchi, Takahiro, Morita, Akira
• Granted Patent: US 9,112,503 B2
• Time in Patent Office: Days
• US Class Current: 361/152
• 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

a resistor and a Zener diode are connected in series in the compensating circuit.

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 compensating circuit has:

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.

4. 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.

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

6. 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 a temperature sensing resistor element, and

the first resistor and the temperature sensing resistor element are connected in series or in parallel.

7. An electromagnetic coil drive device according to claim 6, further comprising a second charging circuit to charge the capacitor based on a stabilized voltage.

8. An electromagnetic coil drive device according to claim 6, wherein the temperature sensing resistor element has a positive temperature coefficient.