PQ7RV4_01 Datasheet, PDF (5/6 Pages) Sharp Electrionic Components – Variable Output(1.5 to 7V), 4.6A Output Low Power-loss Voltage Regulator

Low Power-Loss Voltage Regulators
PQ7RV4
ON/OFF operation is available by mounting externally D2 and R3.
When VADJ is forcibly raised above Vref(1.25V TYP)by applying the external signal,the output is turned off(pass transistor of
regulator is turned off). When the output is OFF, VADJ must be higher than Vref MAX., and at the same time must be lower
than maximum rating 5V.
In OFF-state, the load current flows to RL from VADJ through R2. Therefore the value of R2 must be as high as possible.
In OFF state, as shown below,voltage
VO'=VADJ✕RL/(RL+R2)
occurs at the load. OFF-state equivalent circuit R1 up to 5kΩ is allowed.
Select as high value of RL and R2 as possible in thisrange. In some case, as output voltage is getting lower(VO<1V), impedance
of load resistance rises. In such condition, it is sometimes impossible to obtain the minimum value of VO'. So add the dummy
resistance indicated by RD in the figure to the circuit parallel to the load.