Title:
POWER PROTECTION CIRCUIT
Document Type and Number:
Japanese Patent JP2522146
Kind Code:
B2
Abstract:
PURPOSE: To provide a power protection circuit having a foldback current limiting protection circuit normally operating even when a load having a constant-current characteristic is connected.
CONSTITUTION: A comparator 4 comparing the output voltage level of the foldback current limiting protection circuit 18 with previously decided voltage and outputting a high level when the voltage level of the former becomes larger than that of the latter, a gate part connected to the output of the comparator 4 and FET 5 where the other terminal is connected to the output side of the foldback current limiting protection circuit 18 in parallel are provided. Previously decided voltage is supplied from the sliding terminal of a variable resistor 3 to the comparator 4. When the supply of power to the constant current load 6 through the foldback current limiting protecting circuit 18 is started, current is caused to flow into FET 5 connected to the constant-current load 6 in parallel. When the foldback current limiting protection circuit 18 becomes a normal operation state, FET 5 is controlled by the comparator 4 so as to set it in an off state. Thus, the foldback current limiting protection circuit 18 is normally operated for the load having the constant-current characteristic.
Inventors:
KUMEYA HARUYUKI
Application Number:
JP7723493A
Publication Date:
August 07, 1996
Filing Date:
April 02, 1993
Export Citation:
Assignee:
NIPPON ELECTRIC CO
International Classes:
G05F1/56; H02H9/02; (IPC1-7): G05F1/56; H02H9/02
Attorney, Agent or Firm:
Naoki Kyomoto (2 outside)