SLVSCE3A June 2014 – June 2014 TPS82740A , TPS82740B
PRODUCTION DATA.
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The Power Good comparator features an open drain output. The PG comparator is active with EN pin set to high and VIN is above the threshold VTH_UVLO+. It is driven to high impedance once VOUT trips the threshold VTH_PG+ for rising VOUT. The output is pulled to low level once VOUT falls below the PG hysteresis, VPG_hys. The output is also pulled to low level in case the input voltage VIN falls below the undervoltage lockout threshold VTH_UVLO- or the device is disabled with EN = low. The power good output (PG) can be used as an indicator for the system to signal that the converter has started up and the output voltage is in regulation.
Pin condition | Operating condition | Remark | ||||
---|---|---|---|---|---|---|
PG | EN | CTRL | IOUT / ILOAD | VIN | VOUT | |
hiz | high | high | don't care | > VUVLO | VOUT > VTH_PG+ | PG comparator active, pull up resistor pulls PG to high |
hiz | high | low | medium load (> 1mA) | > VUVLO | VOUT > VTH_PG+ | PG comparator active, pull up resistor pulls PG to high |
hiz | high | low | light load (< 1mA) | > VUVLO | VOUT > VTH_PG+ | PG comparator disabled for low Iq operation, pull up resistor pulls PG to high |
low | high | don't care | 0mA < IOUT < 100mA | > VUVLO | VOUT < VTH_PG- | startup, overload or ramp down |
low | low | don't care | output disabled | VIN > 1.2V | VOUT = 0 | device disabled |
low | high | don't care | output disabled | < VUVLO | VOUT not present | device disabled, due to UVLO |
VOUT pin | EN | VIN condition | remark |
---|---|---|---|
connected to GND, output discharged | low | 1.5V < VIN < VUVLO | |
connected to GND, output discharged | high | < VUVLO | |
hiz, discharge switch disabled | high | > VUVLO | during regulator start up, the discharge switch is enabled and VOUT pulled to low, until the regulator start up time tStart expires. During the softstart time and later, the discharge switch is disabled. |