US 6,608,520 B1Granted

Regulator circuit

AssigneeTexas Instruments Incorporated

InventorTakahiro Miyazaki

Life of this patent

Estimating the term…

Loading patent…

Abstract

To provide a regulator circuit capable of preventing oscillation of output voltage when an overcurrent regulating function is activated voltage across resistor 31 is lower than the voltage of voltage source VR2, output of hysteresis comparator 51 is low-level, n-type MOS transistor 63 is turned off, and capacitor 62 is charged to the voltage level of power supply line Vcc under the normal condition. On the other hand, under an overcurrent condition, hysteresis comparator 51 becomes high-level, n-type MOS transistor 63 is turned on, and the charge in capacitor 62 is discharged. Because differential amplifier circuit 41 selects the signal with a lower voltage out of 2 positive side input signals, negative feedback control is applied to the output voltage in reference to voltage source VR1 under the normal condition, and voltage source 64 under the overcurrent condition. In addition, because the voltage at positive input terminal +2 rises at a fixed rate when moving from the overcurrent condition to the normal condition, sudden changes in the output voltage can be restrained.

Claims6

Dependent claims

A regulator circuit having a voltage output circuit which outputs a voltage in accordance with the level of a voltage control signal input, comprising:

a voltage detection circuit which outputs a voltage detection signal of the level in accordance with the output voltage of the voltage output circuit,
a voltage control signal output circuit which selects either a first voltage setting signal input or a second voltage setting signal of a predetermined level according to the levels of the signals and outputs the voltage control signal in accordance with the difference in level between said voltage setting signal and the voltage detection signal,
an overcurrent detection circuit which detects whether the output current level of the voltage output circuit is in excess of a predetermined overcurrent level or not, and
a voltage setting signal output circuit which sets the level of the first voltage setting signal to a first level not selected by the voltage control signal output circuit when no overcurrent is detected by the overcurrent detection circuit and sets the level of the first voltage setting signal to a second level to be selected by the voltage control signal output circuit when an overcurrent is detected.

1 more element

Dependencies are inferred from the claim text.