NON-INVASIVE LOAD CURRENT SENSING IN LOW DROPOUT (LDO) REGULATORS
First Claim
1. A low dropout (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,a feedback network coupled to the output terminal for providing a voltage feedback signal,an error amplifier coupled between the plurality of PFETs and the feedback network for sensing a differential voltage, wherein an output voltage of the error amplifier is provided to the plurality of PFETs for adjusting the drain of current from each PFET, anda summation of the drains of current from each PFET is provided as the current output to regulate the voltage output at the output terminal.
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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. A sense PFET of the same general size as the plurality of PFETs has gate and source terminals connected, respectively, to the gates and sources of the plurality of PFETs. An error amplifier connected to the regulated voltage output and the drain of the sense PFET supplies an error voltage to the gate of a cascode PFET. A source of the cascode PFET is connected to the drain of the sense PFET. The drain of the cascode PFET provides a sense output current which is Io/n. The error amplifier forces the drain of the sense PFET to be approximately equal to the regulated output voltage and drain the same current as the plurality of PFETs.
18 Citations
20 Claims
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1. A low dropout (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, a feedback network coupled to the output terminal for providing a voltage feedback signal, an error amplifier coupled between the plurality of PFETs and the feedback network for sensing a differential voltage, wherein an output voltage of the error amplifier is provided to the plurality of PFETs for adjusting the drain of current from each PFET, and 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. 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, a sensing network connected to the plurality of PFETs for sensing the level of current drained by each 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 (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification