Methods and apparatus to generate a circuit protection voltage

An input/output (I/O) circuit, the I/O circuit comprising:

• receiver circuitry;
• data driver circuitry;
• and
• protective voltage producing circuitry, the protective voltage producing circuitry comprising:
• circuitry to distribute a first supply voltage to a plurality of circuits, the first supply voltage having a first voltage level;
• circuitry to distribute a second supply voltage to a part of the plurality of circuits, the second supply voltage having a second voltage level;
• circuitry to distribute a protection voltage to the part of the plurality of circuits when the second supply voltage is LOW and the first supply voltage is HIGH, the protection voltage having a voltage level that is a fraction of the voltage level of the first supply voltage;
• and
• circuitry to trigger a distribution of the second supply voltage to the part of the plurality of circuits when the second supply voltage is turned HIGH subsequent to the second supply voltage being LOW when the first supply voltage is HIGH.

A method to produce a protection voltage, the method comprising:

• supplying a first supply voltage to a plurality of circuits, the first supply voltage having a first magnitude;
• supplying a second supply voltage to a part of the plurality of circuits, the second supply voltage having a second magnitude;
• supplying a protection voltage to the part of the plurality of circuits when the second supply voltage is LOW and the first supply voltage is HIGH, the protection voltage having a magnitude that is a fraction of the magnitude of the first supply voltage;
• and
• delivering the second supply voltage to the part of the plurality of circuits when the second supply voltage is turned HIGH subsequent to the second supply voltage being LOW when the first supply voltage is HIGH.