| 摘要 |
<p>A regulator circuit to control the output of a charge pump circuit, to reduce the effects of operating temperature and process variations on available output current from the charge pump circuit. A predetermined fraction of the output voltage of the charge pump circuit is fed back to the input of a differential amplifier, which compares it to a reference voltage. The output of the differential amplifier feeds a voltage controlled oscillator (VCO), which in turn generates a clock signal that is used to drive the charge pump circuit. The normal temperature characteristics of this configuration cause the output of the charge pump circuit to degrade with temperature changes. The regulator circuit can be placed between the differential amplifier and the VCO to adjust the voltage driving the VCO. In one embodiment, a biasing resistor with a negative temperature coefficient can be used in the regulator circuit to offset the normal effects of temperature on the circuit. In another embodiment, multiple such resistors can be selectable with programmable logic, so that process variations during manufacture can be compensated for by selecting the resistor value that most closely provides optimal biasing.</p> |
