Low Dropout Voltage Regulator
First Claim
Patent Images
1. An LDO voltage regulator, comprising:
- an unregulated voltage input port;
a regulated voltage output port;
a differential amplifier having a pair of input terminals and an output terminal, one input terminal connected to a reference voltage;
a voltage divider connected between the regulated voltage output port and a ground reference and having a voltage divider node providing a feedback voltage to the other input terminal of the differential amplifier;
an output pass transistor having a control terminal connected to the output terminal of the differential amplifier, an input terminal connected to the unregulated voltage input port and an output terminal;
a compensation resistor connected between the regulated voltage output port and the output terminal of the output pass transistor; and
a compensation capacitor connected between the output terminal of the output pass transistor and the voltage divider node.
0 Assignments
0 Petitions
Accused Products
Abstract
Improved designs of an LDO voltage regulator with ultra low quiescent current are disclosed. According to one embodiment, an LDO voltage regulator is designed to completely cancel an intermediate gain stage while decreasing a quiescent current and to stabilize a loop circuit by means of two zeros introduced in a frequency transfer function thereof. Such a LDO voltage regulator does not increase the power consumption and applicable in many circuits used in electronic devices.
17 Citations
16 Claims
-
1. An LDO voltage regulator, comprising:
-
an unregulated voltage input port; a regulated voltage output port; a differential amplifier having a pair of input terminals and an output terminal, one input terminal connected to a reference voltage; a voltage divider connected between the regulated voltage output port and a ground reference and having a voltage divider node providing a feedback voltage to the other input terminal of the differential amplifier; an output pass transistor having a control terminal connected to the output terminal of the differential amplifier, an input terminal connected to the unregulated voltage input port and an output terminal; a compensation resistor connected between the regulated voltage output port and the output terminal of the output pass transistor; and a compensation capacitor connected between the output terminal of the output pass transistor and the voltage divider node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. An LDO voltage regulator, comprising:
-
an unregulated voltage input port; a regulated voltage output port; a differential amplifier having a pair of input terminals and an output terminal, one input terminal connected to a reference voltage; a voltage divider connected between the regulated voltage output port and a ground reference and having a voltage divider node providing a feedback voltage to the other input terminal of the differential amplifier; a first output pass transistor having a control terminal connected to the output terminal of the differential amplifier, an input terminal connected to the unregulated voltage input port and an output terminal; a second output pass transistor having a control terminal connected to the output terminal of the differential amplifier, an input terminal connected to the unregulated voltage input port and an output terminal connected to the regulated voltage output port; a compensation resistor connected between the regulated voltage output port and the output terminal of the first output pass transistor; a compensation capacitor connected between the output terminal of the first output pass transistor and the voltage divider node. - View Dependent Claims (10, 11, 12, 13, 14, 15)
-
-
16. An LDO voltage regulator, comprising:
-
first and second output pass transistors having a common gate electrode receiving a control signal, a common source electrode connected to an unregulated voltage input port, an output current of the fist output pass transistor less than an output current of the second output pass transistor, a drain electrode of the second output pass transistor connected to a regulated voltage output port; a compensation resistor connected between the regulated voltage output port and a drain electrode of the first output pass transistor; a compensation capacitor connected between the drain terminal of the first output pass transistor and a voltage feedback node.
-
Specification