Patent ID: 6445166
Filing Date: 2002-09-03
Classification: H02J,H02M

Abstract:
A power supply circuit comprising:a power supply voltage input terminal; a load voltage output terminal; a voltage stabilizer circuit having a first voltage input terminal and a first voltage output terminal, which stabilizes a voltage input to said first voltage input terminal and which outputs a rated voltage from said first voltage output terminal; and a ripple reducing circuit having a second voltage input terminal and a second voltage output terminal, which reduces ripple in a voltage input to said second voltage input terminal and outputs from said second voltage output terminal, wherein said first voltage input terminal and said second voltage input terminal are connected to said power supply voltage input terminal, while said first voltage output terminal and said second voltage output terminal are connected to said load voltage output terminal, and wherein said voltage stabilizer circuit is activated and said ripple reducing circuit is deactivated when a power supply voltage input to said power supply voltage input terminal is at least a predetermined value, so that a voltage output from said voltage stabilizer circuit is output to said load voltage output terminal, while said ripple reducing circuit is activated and said voltage stabilizer circuit is deactivated when said power supply voltage is lower than said predetermined value, so that a voltage output from said ripple reducing circuit is output to said load voltage output terminal.