Low power oscillator with variable duty cycle and method therefor

An oscillator driver circuit having a first node and a second node for coupling to a crystal and providing an oscillator output signal, comprising:

• a first capacitor having a first terminal adapted to be coupled to the first node, and a second terminal coupled to ground;
• a second capacitor having a first terminal adapted to be coupled to the second node, and a second terminal coupled to ground;
• an inverter having an input coupled to the first node, and an output coupled to the second node;
• and
• a voltage shifting circuit coupled to the first node and to the second node and having an input for receiving a tuning signal, wherein said voltage shifting circuit changes an average voltage at the first node according to said tuning signal when an oscillation occurs in response to the crystal being coupled between said first node and said second node.

A method of establishing an oscillation using a crystal, comprising:

• inverting a signal between a first node adapted to be coupled to a first terminal of the crystal and a second node adapted to be coupled to a second terminal of the crystal;
• capacitively coupling said first node to ground;
• capacitively coupling said second node to ground;
• and
• changing an average voltage at the first node during an oscillation that occurs according to a tuning signal when the crystal is coupled between the first node and the second node.