Non-invasive load current sensing in low dropout (LDO) regulators
First Claim
1. An LDO voltage regulator comprising:
- an output terminal for providing a regulated voltage output to a load,a plurality of PFETs connected in parallel, wherein each PFET drains a level of current and the sum of the levels of current are provided as a current output at the output terminal, andall drains of the plurality of PFETs are directly tied together to provide the regulated voltage output to the load,a sensing network, including a sensing PFET, connected to the plurality of PFETs for sensing the level of current drained by each of the plurality of PFETs, wherein the sensing PFET includes a drain, which is not tied to the drains of the plurality of PFETs, andan error amplifier coupled between the output terminal and the sensing network for providing a voltage to the sensing network,wherein a summation of the drains of current from each PFET is provided as the current output to regulate the voltage output at the output terminal, andthe sensing network senses the level of current drained by each PFET of the plurality of PFETs, and provides the sensed level of current as an output control signal.
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Accused Products
Abstract
A low dropout (LDO) voltage regulator includes an output terminal for providing a regulated voltage output to a load, and a plurality of PFETs connected in parallel. Each PFET drains a level of current and the sum of the levels of current are provided as a current output at the output terminal. The LDO voltage regulator also includes a feedback network coupled to the output terminal for providing a voltage feedback signal, and an error amplifier coupled between the plurality of PFETs and the feedback network for sensing a differential voltage. The error amplifier includes an output voltage which is provided to the plurality of PFETs for adjusting the drain of current from each PFET. A summation of the drains of current from each PFET is provided as the current output to regulate the voltage output at the output terminal. Each PFET drains a current level of I0/n and the summation of the drains of current is the current output I0.
23 Citations
12 Claims
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1. An LDO voltage regulator comprising:
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an output terminal for providing a regulated voltage output to a load, a plurality of PFETs connected in parallel, wherein each PFET drains a level of current and the sum of the levels of current are provided as a current output at the output terminal, and all drains of the plurality of PFETs are directly tied together to provide the regulated voltage output to the load, a sensing network, including a sensing PFET, connected to the plurality of PFETs for sensing the level of current drained by each of the plurality of PFETs, wherein the sensing PFET includes a drain, which is not tied to the drains of the plurality of PFETs, and an error amplifier coupled between the output terminal and the sensing network for providing a voltage to the sensing network, wherein a summation of the drains of current from each PFET is provided as the current output to regulate the voltage output at the output terminal, and the sensing network senses the level of current drained by each PFET of the plurality of PFETs, and provides the sensed level of current as an output control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification