| 摘要 |
The present invention discloses a self-bias phase locked loop including a phase frequency detector, a charge pump, a loop filter, a voltage control oscillator, a divider and a bias current converter. A charging or discharging current output from the charge pump equals to a first control current. A resistor of the loop filter is controlled by a first control voltage a second control voltage which is adjusted according to the first control voltage and a second control current. The loop filter boosts or lowers the first control voltage according to the charging or discharging current output from the charge pump. The voltage control oscillator generates a bias current according to the first control voltage and increases or decreases an oscillation frequency according to the boosted or lowered first control voltage, and symmetric loads of the voltage control oscillator are controlled by the first control voltage. The first control current output from the bias current converter equals to the ratio of the bias current to a constant, and the second control current output from the bias current converter equals to the ratio of the bias current to a frequency division factor. The circuit of the self-bias phase locked loop is simple and a low jitter.
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