Freescale Semiconductor,inc.

Nidhi Chaudhry

Parul K Sharma

Amit Kumar Srivastava

Ravi Dixit

A voltage clamping circuit that is implemented using low voltage devices provides a way to discharge an input/output pin to ground during overvoltage conditions and to avoid any interaction between the input/output pin and the input/output supply during clamping action. The voltage clamping circuit is also self-protected. A voltage detection circuit detects an overvoltage condition and in response generates a signal that turns on a PMOS, which in turn provides a clamping current path between the input/output pin and ground.

Voltage clamping circuit

A circuit for scaling down first and second input voltages includes first and second voltage scale-down circuits that scale down the first and second input voltages, respectively. The first voltage scale-down circuit includes a transistor that receives the first input voltage at its gate and, operating in a source-follower configuration, scales down the first input voltage to generate a first output voltage at its source. The second voltage scale-down circuit is identical to the first voltage scale-down circuit and generates a second output voltage based on the second input voltage.

Voltage scale-down circuit

An embedded system includes a level shifter circuit for generating a forward supply voltage level in a predefined range. A sense circuit senses a core supply voltage level of the embedded system and compares the sensed core supply voltage level with a predetermined minimum core supply voltage level needed to generate the forward supply voltage. A reset circuit maintains one or more input nodes and one or more internal nodes of the level shifter circuit at a predetermined voltage level when the core supply voltage level is less than the predetermined minimum core supply voltage level.

Level shifter circuit

A voltage clamping circuit for protecting an input/output (I/O) terminal of an integrated circuit from over shoot and under shoot voltages includes transistors connected to form a current conducting path. A voltage at the I/O pin is detected using a voltage detection circuit. The current conducting path is switched on when the voltage at the I/O pin exceeds a predetermined value.

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Ghaziabad, India

Nidhi Chaudhry