PROTECTING CIRCUIT FOR POWER TRANSISTOR BRIDGE CIRCUIT

Title:

PROTECTING CIRCUIT FOR POWER TRANSISTOR BRIDGE CIRCUIT

Document Type and Number:

Japanese Patent JPS5947996

Kind Code:

A

Abstract:

PURPOSE:To protect a bridge circuit for controlling the pulse width modulation of a servo motor by detecting the overcurrent flowed to two power transistors of earth side, thereby breaking the base input of the transistor. CONSTITUTION:An AC power source 15 energizes a bridge circuit which has power transistors (TR)2-4 through a rectifier 14, and controls the pulse width modulation of a servo motor 1. When the TR2, 3 or 4, 5 are simultaneously conducted to flow an overcurrent, it is detected by noninduction resistor 27 or 28, and applied to a base controller 29 or 30 with an overcurrent detector. The detected voltage is supplied to the noninverting input terminal 32 of a comparator 31 which is provided in the controller 29, 30 to turn ON a thyristor 33 when larger than the comparison reference voltage to shortcircuit between the connecting terminal connected to the base terminal of the TR3 or 5 and the earth. Accordingly, the base input of the TR3 or 4 is interrupted, thereby protecting the bridge circuit.

Inventors:

KAKEI SHINOBU
KINOSHITA HISASHI
YOSHITAKE HIDEKI

Application Number:

JP15670982A

Publication Date:

March 17, 1984

Filing Date:

September 10, 1982

Export Citation:

Click for automatic bibliography generation Help

Assignee:

MATSUSHITA ELECTRIC IND CO LTD

International Classes:

H02P7/288; H02P7/00; (IPC1-7): H02P7/28

Attorney, Agent or Firm:

Koji Hoshino

Previous Patent: The coffee mill hopper of the two or more division drawing for a coffee mill

Next Patent: JPS5947997