| 摘要 |
PURPOSE:To reduce the power loss of a switching regulator by controlling a quasi-load current by the variation in an output current at no-load time, and interrupting it at the prescribed output current or larger time. CONSTITUTION:An output circuit of a switching regulator has a smoothing choke coil 1, a capacitor 3, a current detecting resistor 4, a quasi-load current control error amplifier 5, a drive transistor 8, and quasi-load current interrupting condition setting resistors 6, 7. Thus, a voltage divided from an output voltage Vout is obtained at both ends of the resistor 7, and a voltage of the sum of an output current I0 and the quasi-load current ID is obtained at both ends of the resistor 4. Thus, the voltage applied to the non-inverting input terminal of the amplifier 5 generates a voltage equal to the sum of the both voltages. Even if the current I0 decreases, the current ID can be so increases as to maintain the current flowed to the resistor 4 at the constant current at no-load or light-load time. |
