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US 11,309,882 B2Granted
OPAMP overload power limit circuit, system, and a method thereof
AssigneeTexas Instruments Incorporated
InventorsSudarshan Udayashankar, Martijn Fridus Snoeij
Life of this patent
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Abstract
An amplifier overload power limit circuit, system, and a method thereof comprising a monitoring of a current gain of a BJT based on a current detector and limiting power to the BJT based on the monitored current gain to prevent the BJT from driven into a saturation mode and the amplifier overdrive.
Claims8
A method for limiting power to a bipolar junction transistor (BJT) amplifier, comprising:
- monitoring a current gain of a BJT of the BJT amplifier;
- comparing the current gain with a preset value;
- and
- limiting a base current to the BJT based on the comparison;
- wherein the monitoring of the current gain comprises,
- detecting an emitter or collector current of the BJT;
- detecting a base current of the BJT;
- and
- determining a ratio of the emitter or collect current to the base current, and wherein the current gain comprises the ratio of the emitter or collector current to the base current.
6 more elements
A BJT amplifier system comprising,
- a BJT amplifier with a BJT;
- a current detector coupled to the BJT amplifier;
- and
- a limiting circuit coupled to the BJT amplifier and the current detector,
- wherein the current detector is configured to detect a current gain of the BJT and enable or disable the limiting circuit based on the current gain, and the limiting circuit configured to limit the base current supply to the BJT based on the current gain when enabled;
- wherein the current detector comprising,
- a base current sensor coupled to a base node of the BJT;
- an emitter current sensor coupled to an emitter node of the BJT;
- and
- a comparator coupled to the base current sensor, the emitter current sensor, and the limiting circuit,
- wherein the base current sensor is configured to sense a base current of the BJT, the emitter current sensor is configured to sense an emitter current of the BJT, and the comparator is configured to compare a ratio of the emitter current to the base current with a preset value and enable or disable the limiting circuit based on the comparison;
- and
- wherein the current gain comprises the ratio of the emitter current to the base current.
10 more elements
Dependencies are inferred from the claim text.