Title:
【発明の名称】電源回路
Document Type and Number:
Japanese Patent JPH10513637
Kind Code:
A
Abstract:
In a self-oscillating power-supply circuit for charging a battery (B) the switching transistor (T2) is turned off if the voltage across the sensing resistor (R3) exceeds the threshold voltage of a zener diode (D5). Instead of the zener diode (D5) it is possible to use a switching transistor which is actuated when the current through the switching transistor exceeds a given value. A diode (D6) is arranged in series with the zener diode (D5) 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 may be added to monitor the battery voltage and to eliminate the short-circuit of the diode (D6) when a given battery voltage is reached, as a result of which the power-supply circuit changes over to slow charging. A cascode transistor (T1) reduces the dissipation of the switching transistor (T2), protects the switching transistor (T2) against overvoltage and stabilizes the voltage on the supply terminal (N3) to which the starting resistor (R6) is connected. This allows an accurate dosing of the current during slow charging.
Inventors:
Herringa Schelte
Application Number:
JP52031197A
Publication Date:
December 22, 1998
Filing Date:
November 18, 1996
Export Citation:
Assignee:
Philips Electronics Nemrose Fennaught Shap
International Classes:
H02J7/02; H02J7/10; H02M3/28; H02M3/338; B26B19/38; (IPC1-7): H02M3/28; H02J7/10; B26B19/38
Attorney, Agent or Firm:
Akihide Sugimura (6 others)