Charge Pump Regulator for Color TFT Panel
The ADM8832 has an internal 100 kHz oscillator for use in scanning mode, but the part must be clocked by an external clock source in blanking (low current) mode. The internal oscillator is used to clock the charge pumps during scanning mode where the current is highest. During blanking periods, the ADM8832 switches to use an external, lower frequency clock. This allows the user to vary the frequency and maximize power efficiency during blanking periods. The tolerances on the output voltages are seamlessly maintained when switching from scanning mode to blanking mode or vice versa.
The ADM8832 has a number of power saving features, including low power shutdown and reduced quiescent current consumption during the blanking periods mentioned above. The 5.1 V output consumes the most power, so power efficiency is also maximized on this output with an oscillator enabling scheme (Green Idle™). This effectively senses the load current that is flowing and turns on the charge pump only when charge needs to be delivered to the 5 V pump doubler output.
The ADM8832 is fabricated using CMOS technology for minimal power consumption. The part is packaged in a 20-lead LFCSP (lead frame chip scale package).
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