UPD16874 查看數據表（PDF） - NEC => Renesas Technology

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UPD16874

QUAD Pch HIGH-SIDE SWITCH FOR USB

NEC => Renesas Technology 

µPD16874

DESCRIPTION OF FUNCTIONS

1. Overcurrent Detection

This IC detects an overcurrent in a range of 0.6 to 1.25 A (0.9 A TYP.) (the USB Standard defines that an

overcurrent is 0.5 A MAX.). When the IC detects an overcurrent, the FLG pin goes low (active) and reports the result

of detection to the control IC. At this time, the switch is kept ON and the current limiter is activated. In this way, an

overcurrent status that lasts for a long time can be prevented.

By deasserted the CTL pin inactive by the control IC, the switch is turned OFF and the FLG pin goes back high.

Therefore, the CTL signal must be deasserted inactive as soon as the controller IC has detected that the FLG pin has

gone low, to avoid overheating this IC. Once the switch has been turned OFF, it turns back ON again only when the

CTL signal is asserted active while the FLG pin is high.

To prevent an inrush current being detected by mistake, a deadband time (overcurrent detection delay time) is set

to elapse before the overcurrent detector is activated. The duration of this deadband time is 20 µs TYP.

While the overcurrent limiter is activated, the power consumption of the device may abruptly increase. As a result,

the junction temperature may also rise. Make sure that the CTL signal is deasserted inactive and that the switch is

turned OFF before the absolute maximum rating is exceeded.

2. Undervoltage Lockout Circuit (UVLO)

This circuit prevents malfunctioning of the switch due to fluctuation in supply voltage.

When power is turned on (2.5 V or less TYP.) or off (2.3 V or less TYP.), the OUT and FLG pins have the following

status:

OUT: OFF

FLG: “L” (= 0 V)

5V

Output voltage

2.3 V 2.5 V

5V

Input voltage

The above figure does not show the actual waveform. For the related characteristic waveform, refer to Major

Characteristic Curves.

6

Data Sheet S13894EJ1V0DS

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