The bq2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than 1% over the operating-temperature and supply-voltage ranges. For single and dual cells with either coke or graphite anodes, the bq2057 is offered in four fixed-voltage versions: 4.1V, 4.2V, 8.2V, and 8.4V. Charge stops when the current tapers to the ch a r g e t e r m i n a t i o n t h r e s h o l d , VTERM. The bq2057 automatically restarts the charge if the battery voltage falls below the VRCH threshold. The designer also may use the