Qualcomm Incorporated

Bing Liu

Vincenzo Peluso

Troy L Stockstad

Joseph Dale Rutkowski

Ngai Yeung Ho

Liangguo Shen

Vincenzo F Peluso

The present disclosure includes circuits and methods for generating bleeding currents. In one embodiment, a pass transistor of a voltage regulator receives a voltage from a feedback circuit. A negative resistance circuit is coupled to a node to produce a bleeding current that turns on when needed and is otherwise off to save power. In one embodiment, the negative resistance circuit includes stacked current mirrors and a resistor. In another embodiment, the resistor has a first terminal that receives the voltage from the feedback circuit and a second terminal is coupled to a constant reference voltage that tracks the input voltage.

Low dropout regulator bleeding current circuits and methods

In one embodiment, a circuit includes a first transistor having a control terminal, a first terminal, and a second terminal where the first transistor is a first device type. The control terminal of the first transistor receives an input signal. The circuit also includes a second transistor having a control terminal, a first terminal, and a second terminal where the second transistor is a second device type. The control terminal of the second transistor is coupled to the second terminal of the first transistor. A voltage shift circuit has an input coupled to the first terminal of the first transistor and an output coupled to the first terminal of the second transistor and a voltage between the input of the voltage shift circuit and an output of the voltage shift circuit increases as a current from the output of the voltage shift circuit increases.

Buffer circuit for a LDO regulator

In one embodiment, a circuit comprises a current source to produce current to a light emitting diode array. An analog dimming circuit generates a continuous control signal to the current source to control the current in the light emitting diode array according to a range of control signal values when the control signal is above a threshold. Below the threshold, a digital modulation circuit generates an additional modulated digital signal to the current source to control the current in the light emitting diode array according to a range of modulation values when the continuous control signal is below the threshold. The continuous control signal produces current from the current source into the light emitting diode array above a first value. The combination of the continuous control signal and the modulated digital signal produces current in the light emitting diode array below the first value.

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San Diego, CA, United States of America

Bing Liu