Power-up Control for Very Low-Power Systems
First Claim
1. An input protection circuit comprising:
- a first circuit configured to compare an input signal to a reference signal, and generate a first control signal indicative of whether the value of the input signal is greater than or equal to the value of the reference signal, or less than the value of the reference signal;
a second circuit configured to receive the first control signal, and generate a second control signal according to the first control signal, wherein the second control signal is set to a first specified value for a first value of the first control signal, and wherein a value of the second control signal tracks the value of the input signal for a second value of the first control signal; and
a third circuit configured to generate an output signal according to the first control signal and the second control signal, wherein a value of the output signal tracks the value of the input signal for the first value of the first control signal and the first specified value of the second control signal, and wherein the value of the output signal is set to a second specified value less than the value of the input signal for the second value of the first control signal.
10 Assignments
0 Petitions
Accused Products
Abstract
An input protection circuit (IPC) may prevent an input signal from propagating into a system, such as an integrated circuit (IC), when the voltage level of the input signal exceeds a specified value. The IPC may be configured to compare the input signal voltage, which may be that of an external input signal received by the system, with a reference voltage, which may be the power supply voltage. If the input signal voltage exceeds the reference voltage, the output of the IPC may be set to the value of a specified clamp voltage. If the input signal voltage does not exceed the reference voltage, the output of the IPC may track (or follow) the input signal voltage. For certain integrated circuits, the IPC may be configured to provide circuit protection for an input signal voltage ranging between 0V to 5V, and a power supply voltage ranging between 3.0V and 3.6V.
24 Citations
25 Claims
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1. An input protection circuit comprising:
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a first circuit configured to compare an input signal to a reference signal, and generate a first control signal indicative of whether the value of the input signal is greater than or equal to the value of the reference signal, or less than the value of the reference signal; a second circuit configured to receive the first control signal, and generate a second control signal according to the first control signal, wherein the second control signal is set to a first specified value for a first value of the first control signal, and wherein a value of the second control signal tracks the value of the input signal for a second value of the first control signal; and a third circuit configured to generate an output signal according to the first control signal and the second control signal, wherein a value of the output signal tracks the value of the input signal for the first value of the first control signal and the first specified value of the second control signal, and wherein the value of the output signal is set to a second specified value less than the value of the input signal for the second value of the first control signal. - View Dependent Claims (2, 3, 4, 5)
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6. A protection circuit comprising:
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a first component configured to; receive an input voltage and a reference voltage; assert a first control signal when the input voltage is greater than or equal to the reference voltage; and deassert the first control signal when the input voltage is less than the reference voltage; a second component configured to; deassert a second control signal when the first control signal is deasserted; set the second control signal to track the input voltage when the first control signal is asserted; and a third component configured to; set an output voltage to a specified voltage less than the input voltage when the first control signal is asserted; and set the output voltage to track the input voltage when the first control signal and the second control signal are both deasserted. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A method for protecting a system from high voltage, the method comprising:
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comparing an input voltage to a reference voltage; generating a first control signal in response to said comparing, wherein the first control signal is indicative of whether the input voltage is greater than or equal to the reference voltage, or less than the reference voltage; setting a second control signal; to a first specified voltage in response to the first control signal indicating that the input voltage is less than the reference voltage; and to the input voltage in response to the first control signal indicating that the input voltage is greater than or equal to the reference voltage; and setting an output; to a second specified voltage less than the input voltage in response to the first control signal indicating that the input voltage is greater than or equal to the reference voltage; and to the input voltage in response to; the first control signal indicating that the input voltage is less than the reference voltage; and said setting the second control signal to the first specified voltage. - View Dependent Claims (15, 16, 17, 18)
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19. An integrated circuit comprising:
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a function block; at least one input pin configured to receive an input signal intended for at least one specific destination within the function block, the input signal having a voltage value; and a protection circuit coupled between the at least one input pin and the function block, wherein the protection circuit is configured to; allow the input signal to propagate to the at least one specific destination within the function block when the voltage value of the input signal does not exceed the value of a specified reference voltage; and provide a replacement signal to propagate to the at least one specific destination within the function block instead of the input signal when the voltage value of the input signal exceeds the value of the specified reference voltage, wherein the voltage value of the replacement signal is no greater than the value of a supply voltage configured to power the integrated circuit, and wherein the voltage value of the replacement signal corresponds to the logic level represented by the voltage value of the input signal. - View Dependent Claims (20, 21)
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22. A method for protecting a system against high voltage, the method comprising:
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receiving an input signal intended for at least one specific destination within the system, the input signal having a voltage value; intercepting the input signal before it reaches the at least one specific destination within the system; allowing the input signal to propagate to the at least one specific destination within the system when the voltage value of the input signal does not exceed the value of a specified reference voltage; and generating a replacement signal to replace the input signal when the voltage value of the input signal exceeds the value of the specified reference voltage, wherein the voltage value of the replacement signal is no greater than the value of a supply voltage configured to provide power to the system, and wherein the voltage value of the replacement signal corresponds to the logic level represented by the voltage value of the input signal. - View Dependent Claims (23, 24, 25)
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Specification