Control circuit for a dc motor

• US 6,321,031 B1
• Filed: 06/02/1999
• Issued: 11/20/2001
• Est. Priority Date: 07/25/1997
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Mohr, Thomas, Kern, Robert, Preis, Karl-Heinrich, Schwenk, Wolfgang
• Primary Examiner(s): Nappi, Robert E.
• Assistant Examiner(s): Duda, Rina I.
• Application Number:
  US09/269,604
• Time in Patent Office: 902 Days
• Field of Search: 318/139, 318/286, 318/287, 318/439, 388/801, 388/806
• US Class Current: 388/801
• CPC Class Codes: H02H 11/003 using a field effect transistor as protecting element in one of the supply lines
• CPC Class Codes: H02P 7/29 using pulse modulation

Abstract

A control circuit for a direct-current motor driven in a clocked manner, includes an electrolytic capacitor connected in parallel and free-wheeling diode. Spurious radiation is reduced, in that a choke is connected between the positive motor supply voltage and the plus terminal of the electrolytic capacitor, and that the free-wheeling diode is disposed with its cathode between the choke and the electrolytic capacitor, and with its anode on the negative side of the d.c. motor.

Claims

1. A control circuit arrangement for a direct-current motor, the motor being driven in a clocked manner, comprising:

an electrolytic capacitor connected in parallel with the motor;

a choke coupled between a positive motor supply voltage and a plus terminal of the electrolytic capacitor;

a free-wheeling diode including a cathode and an anode, the cathode being coupled between the choke and the electrolytic capacitor, the anode being coupled to a negative motor supply voltage; and

a polarity reversal protection device;

wherein the polarity reversal protection device is coupled between the choke and the positive motor supply voltage.

2. The control circuit arrangement according to claim 1, wherein the polarity reversal protection device includes an inversely operated n-channel power MOSFET.

3. A control circuit arrangement for a direct-current motor, the motor being driven in a clocked manner, comprising:

an electrolytic capacitor connected in parallel with the motor;

a choke coupled between a negative motor supply voltage and a minus terminal of the electrolytic capacitor; and

a free-wheeling diode including a cathode and an anode, the anode being coupled between the choke and the electrolytic capacitor, the cathode being coupled to a positive motor supply voltage.

4. The control circuit arrangement according to claim 3, further comprising:

a polarity reversal protection device including an inversely operated n-channel power MOSFET, the polarity reversal protection device being coupled between the choke and the negative motor supply voltage.