Microtune (san Diego), Inc.

Ee Hong Kwek

Jonathon Cheah

Shih-Tsung Yang

Chun-Yip Antony Lau

Chee Kwang Quek

A method and apparatus for tuning a VCO circuit to provide desired modulations is described. In one embodiment, the method of the present invention uses a controlled voltage from a digital-to-analog converter to obtain VCO voltage/frequency characteristics. The VCO voltage/frequency characteristics are used to determine a VCO capacitance value as well as a charge pump current level for each frequency band of interest. For one embodiment, the VCO circuit includes a bank of switchable capacitors used to set the VCO capacitance value. The charge pump includes a number of switch-controlled current meters to set the charge pump current level. The VCO capacitors and charge pump current meters are controlled by an off-chip CPU.

Methods and apparatuses for tuning voltage controlled oscillators

An in-chip monitoring method and apparatus are disclosed. In one embodiment the apparatus includes a test pad, a transmission gate and a plurality of test components coupled to the transmission gate. The transmission gate is attached to a substrate and adapted to receive a code word uniquely addressed to one of the plurality of test components. In a further embodiment, the transmission gate is further adapted to relay an output of the one of the plurality of test components to the test pad, in response to receipt of the code word.

In-chip monitoring system to monitor input/output of functional blocks

A VCO circuit for a fractional-n PLL circuit is described for implementing a direct modulation scheme. An embodiment of the invention provides a bank of switchable capacitors used to stringently control the gain of the VCO (KVCO). The capacitors provide the stringent control necessary for direct modulation. The bank of switchable capacitors is used to coarsely tune the VCO circuit. A linear capacitor is placed in series with, the varactor to linearize the frequency/capacitance response of the varactor. The capacitor also serves to isolate a reference voltage that is used to bias the varactor diode to ensure the linear range of the varactor is within the voltage range of the VCO circuit power supply. The varactor is used for fine tuning of the VCO circuit. For one embodiment the input voltages to the VCO are across a resistance value sufficient to dampen noise picked up through an external loop filter.

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San Diego, CA, United States of America

Ee Hong Kwek