ZHCS996D June 2012 – February 2018 TPS81256
PRODUCTION DATA.
請(qǐng)參考 PDF 數(shù)據(jù)表獲取器件具體的封裝圖。
The TPS81256 device starts operation when EN is set high and starts up with the soft-start sequence. For proper operation, the EN pin must be terminated and must not be left floating.
The TPS81256 device has an internal softstart circuit that limits the inrush current during start-up. The first step in the start-up cycle is the pre-charge phase. During pre-charge, the rectifying switch is turned on until the output capacitor is charged to a value close to the input voltage. The rectifying switch is current limited (approx. 200mA) during this phase. This mechanism is used to limit the output current under short-circuit condition.
Once the output capacitor has been biased to the input voltage, the converter starts switching. The soft-start system progressively increases the on-time as a function of the input-to-output voltage ratio. As soon as the output voltage is reached, the regulation loop takes control and full current operation is permitted.
Pulling the EN pin low forces the device in shutdown, with a shutdown current of typically 1µA. In this mode, true load disconnect between the battery and load prevents current flow from VIN to VOUT, as well as reverse flow from VOUT to VIN.