High-voltage, bidirectional protection circuits and methods
AssigneeMaxim Integrated Products, Inc.
InventorGabriel Eugen Tanase
Life of this patent
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Abstract
Systems and methods herein use a sensing circuit to detect an overvoltage at a voltage node as a drain current. A current-mode comparator converts the detected current into a control signal, which is provided to a control circuit. The control circuit uses the control signal cut of a bias current to turn off switches in a protection circuit to create a high-impedance electrical path between the voltage node and the to-be-protected voltage node.
Claims20
An overvoltage protection method comprising:
- using a sensing circuit that, in response to an overvoltage condition being present at a voltage node, detects a current;
- using a current-mode comparator to convert the current to a control signal;
- and
- using a control circuit that, in response receiving the control signal, turns off a set of switching devices that are coupled to a to-be-protected voltage node to create a high-impedance electrical path between the voltage node and the to-be-protected voltage node.
A dual-polarity high-voltage protection circuit comprising:
- a protection circuit coupled to a to-be-protected voltage node and an output voltage node;
- a voltage sensing circuit that, in response to sensing an overvoltage condition present at the output voltage node, generates an output signal indicative of the overvoltage condition;
- and
- a control circuit coupled to the voltage sensing circuit, the control circuit, in response to receiving the output signal, causes the protection circuit to assume a high impedance to isolate the to-be-protected voltage node from the overvoltage condition.
A switch network for bidirectional high-voltage protection of a voltage node, the switch network comprising:
- two sets of switches that each is coupled to a to-be-protected voltage node and an output voltage node, which in normal operation assumes a voltage within a voltage range;
- a set of comparators that each is coupled to a switch in a third set of switches, respectively, and generates a low-level signal to control bias currents to cause the two sets of switches to turn on, such that the voltage drop between the to-be-protected voltage node and the output voltage node is determined by on-resistances of the two sets of switches and a load current flowing through the output voltage node;
- and
- in response to the voltage at the output voltage node falling outside the voltage range, a drain current exceeding a current value causing a corresponding comparator in the set of comparators generating a high-level signal that causes the bias currents and, thus, the two sets of switches to turn off, thereby, creating a high-impedance path between the to-be-protected voltage node and the output voltage node, the voltage at the to-be-protected voltage node being controlled by an output stage state of an operational amplifier to be within the voltage range, the voltage at the output voltage node assuming values between a negative high voltage and a positive high voltage.
Dependencies are inferred from the claim text.