Low dropout regulator with wide input voltage range
First Claim
Patent Images
1. A low dropout regulator comprising:
- an input terminal, for receiving an input voltage;
an output terminal, for outputting an output voltage from the input voltage after regulating;
a N-type pass transistor, for supplying power from the input terminal to the output terminal, the N-type pass transistor having a drain terminal, a source terminal, and a gate terminal, wherein the drain terminal is coupled to the input terminal, and the source terminal is coupled to the output terminal;
a P-type pass transistor, for supplying power from the input terminal to the output terminal, the P-type pass transistor having a drain terminal, a source terminal, and a gate terminal, wherein the source terminal is coupled to the input terminal, and the drain terminal is coupled to the output terminal; and
a control circuit, for controlling the gate terminals of the N-type pass transistor and the P-type pass transistor to turn-one one of the N-type pass transistor and the P-type pass transistor to output the regulated voltage and to turn-off another of the N-type pass transistor and the P-type pass transistor;
wherein the control circuit includes two error amplifiers, being used to control the N-type pass transistor for generating a first output voltage at the output terminal and to control the P-type pass transistor for generating a second output voltage at the output terminal.
5 Assignments
0 Petitions
Accused Products
Abstract
A low dropout (LDO) regulator operates in wide input range. The LDO includes an N-type pass transistor and a P-type pass transistor for supplying power to the output terminal. The P-type pass transistor is connected with N-type pass transistor in parallel. Two error amplifiers control the gate terminals of the N-type pass transistor and P-type pass transistor to generate a first output voltage and a second output voltage. Thus, the first output voltage is generated when the input voltage is higher than a threshold voltage, and the second output voltage is generated when the input voltage is lower than the threshold voltage.
-
Citations
9 Claims
-
1. A low dropout regulator comprising:
-
an input terminal, for receiving an input voltage; an output terminal, for outputting an output voltage from the input voltage after regulating; a N-type pass transistor, for supplying power from the input terminal to the output terminal, the N-type pass transistor having a drain terminal, a source terminal, and a gate terminal, wherein the drain terminal is coupled to the input terminal, and the source terminal is coupled to the output terminal; a P-type pass transistor, for supplying power from the input terminal to the output terminal, the P-type pass transistor having a drain terminal, a source terminal, and a gate terminal, wherein the source terminal is coupled to the input terminal, and the drain terminal is coupled to the output terminal; and a control circuit, for controlling the gate terminals of the N-type pass transistor and the P-type pass transistor to turn-one one of the N-type pass transistor and the P-type pass transistor to output the regulated voltage and to turn-off another of the N-type pass transistor and the P-type pass transistor; wherein the control circuit includes two error amplifiers, being used to control the N-type pass transistor for generating a first output voltage at the output terminal and to control the P-type pass transistor for generating a second output voltage at the output terminal. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A regulating method by a low dropout regulator, the low dropout regulator includes an N-type pass transistor, a P-type pass transistor, a control circuit, an input terminal and an output terminal, comprising the following steps:
-
receiving an unregulated DC voltage by the input terminal; generating a first output voltage to the output terminal by the N-type pass transistor regulates the unregulated DC voltage when the unregulated DC voltage is higher than an input threshold; and generating a second output voltage to the output terminal by the P-type pass transistor regulates the unregulated DC voltage when the unregulated DC voltage is lower than an input threshold. - View Dependent Claims (8, 9)
-
Specification