RT7204E

F

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RT7204E_DS-00

May 2024

38

16.7

VBUS Drop Protection

The VBUS drop protection provides an additional mechanism to protect the output short circuit, as shown in Figure

14. It is designed to detect the voltage difference between VDD and VBUS, which includes current-sense resistor

and blocking N-MOSFET drain-to-source. When the voltage difference exceeds the VBUS drop threshold, the

blocking N-MOSFET will be clamped-off immediately.

VVBUS_DROP

N-MOSFET

Driver

IOUT

Debounce

Time

Reset Signal

+

-

USBP

VBUS

VDD

Q

Q

R

S

VOUT

VBUS

RCS

Figure 14. VBUS Drop Protection

16.8

Temperature Sensing and Thermal Protection

The RT7204E provides the RT pin for over-temperature protection or thermal monitoring. As shown in Figure 2,

the RT pin sources a constant bias current for a remote thermal sensor of an NTC thermistor, connected from the

RT pin to GND, for temperature sensing. If the RT voltage falls below a programmable threshold voltage and the

condition sustains for a programmable deglitch time, the over-temperature protection will be triggered.

The bias current passing through the RT pin can be programmed to either 100

A or 20A via a register setting.

Selecting the appropriate bias current enhances the linearity of the temperature sensing function across a

temperature range of 25°C to 100°C. Additionally, The RT7204E can transmit the sensed RT voltage signal to the

UFP via the protocol (Vendor Defined Message), if necessary. Figure 15 shows the RT voltages vary with

temperature at two different bias currents using an NTC thermistor TTC104 as an example.

2.5V

0.4V

1V

2V

100°C

50°C

0°C

20µA

100µA

VRT

Temperature

Figure 15. The RT Voltages vs. Temperature