| 摘要 |
A circuit for counting pulses which may be used, for example, to provide a power on reset signal after power is applied to a circuit, employing charge transfer between two capacitors. The counter charges a first capacitor to a first voltage level between input pulses. During each input pulse, a portion of the charge stored on the first capacitor is transferred to the second capacitor. The voltage across the second capacitor increases with each input pulse. When the voltage on the second capacitor reaches a predetermined threshold level, an output signal is provided by a threshold detector to indicate that a predetermined number of input pulses has been counted. The second capacitor is then discharged in order to reset the pulse counter before beginning another counting cycle.
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