Title:
【発明の名称】電源回路
Document Type and Number:
Japanese Patent JPH10513636
Kind Code:
A
Abstract:
In a self-oscillating power-supply circuit for charging a battery, a switching transistor (T2) is turned off if the voltage across a sensing resistor (R3) exceeds the threshold voltage of a zener diode (D5). The zener diode is arranged in parallel with the series arrangement of the base-emitter junction of the switching transistor and the sensing resistor, so that the voltage of the battery does not influence the peak current at which the switching transistor is turned off. A diode (D6) is arranged in series with the zener diode and can be short-circuited by means of a switch (T3) in order to switch the power-supply circuit from slow charging to rapid charging. A voltage sensor (R8, R9, T4) monitors the battery voltage and eliminates the short-circuit of the diode (D6) when a given battery voltage is reached so that the power-supply circuit changes over to slow charging. A cascode transistor (T1) protects the switching transistor against overvoltage and stabilizes the voltage on the supply terminal (N3) to which a starting resistor (R6) is connected. This allows an accurate dosing of the current during slow charging.
Inventors:
Herringa Schelte
Application Number:
JP52031097A
Publication Date:
December 22, 1998
Filing Date:
November 18, 1996
Export Citation:
Assignee:
Philips Electronics Nemrose Fennaught Shap
International Classes:
H02J7/10; H02M3/28; H02M3/338; B26B19/38; (IPC1-7): H02M3/28; B26B19/38; H02J7/10
Attorney, Agent or Firm:
Akihide Sugimura (6 others)