CPC H01S 5/0428 (2013.01) [H03K 17/6871 (2013.01); H03K 19/20 (2013.01)] | 12 Claims |
1. An apparatus comprising:
a refresh circuit configured to receive a DC input voltage and to provide a refresh current to a capacitor using the DC input voltage, wherein a current amplitude of the refresh current is controlled by the refresh circuit based on a voltage developed at the capacitor in response to the refresh current; and
wherein the refresh circuit comprises:
an attenuator circuit configured to generate a representative voltage signal based on the voltage developed at the capacitor;
a threshold voltage generator circuit configured to generate a plurality of threshold voltages based on a specified maximum target voltage that the capacitor should be charged to;
a plurality of comparators configured to generate a plurality of comparison signals based on respective comparisons of the representative voltage signal to the plurality of threshold voltages; and
a drive configuration circuit configured to receive the plurality of comparison signals and to control the amplitude of the refresh current based on the plurality of comparison signals.
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