RT7207 datasheet(23/25 Pages) RICHTEK

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RT7207

DS7207-00 January 2017

www.richtek.com

is a registered trademark of Richtek Technology Corporation.

USBP Control

The RT7207 provides an open-drain driver for controlling

an external blocking P-MOSFET. Once the communication

is set up with an UFP, or a 5.1k

Ω resistor at the CC1/CC2

pin of a Type-C connector of the UFP is detected, the P-

MOSFET will be turned on. If VOUT over-voltage condition

occurs, the blocking P-MOSFET will be turned off to

prevent the UFP from being damaged by the VOUT over-

voltage condition. If VOUT is shorted to GND, the P-

MOSFET will also be turned off automatically so that

output power can be limited.

Output Over-Voltage Protection

As shown in the Figure 12, the RT7207 provides the OVP

pin as a backup VOUT over-voltage protection, in case the

optocoupler of the feedback loop is malfunction due to

aging. If the internal voltage related to VDD is higher by

the programmable threshold VVOUT_OVP, the OVP pin will

be pulled low. The OVP pin voltage will be latched low

until the VDD voltage drops below the VDD turn-off

threshold VVDD_OFF, as shown in Figure 13.

Figure 11. The RT Voltages vs. Temperature at Three Bias

Currents

Figure 9. (a) VOUT Rises. (b) VOUT Falls.

(b)

Figure 10. Application Circuit of an Active Dummy Load

Temperature Sensing and Thermal Protection

The RT7207 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

is below a programmable threshold voltage and the

condition sustains for a programmable deglitch time, over-

temperature protection will be triggered.

The bias current through the RT pin can be programmed

as 100

μA, 20μA, or 4μA by setting the internal register.

With the appropriate bias current setting, linearity of

temperature sensing over the temperature range of 25

°C

to 100

°C can be improved. The RT7207 can deliver the

sensed RT voltage data back to the UFP via the protocol

(Vendor Defined Message), if necessary. Figure 11 shows

the RT voltages vary with temperature at three different

bias currents with an NTC thermistor TTC104 as an

example.

2.5V

0.4V

100°C

50°C

0°C

20µA

4µA

100µA

VRT

Temperature

DOL

BLD

DIEN

COUT

RDUMMY

20V

VOUT

VREF_CV

2.5V

200µs

SR_EN

VBLD

300ms (programmable)

<275ms

Slope -1.875V / 275ms

-5mV/750µs



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RT7207 Datasheet(PDF) 23 Page - Richtek Technology Corporation

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