VOUT

ILIM

VOUT

FB

GND

LM3492HC-Q1, LM3492HC

SNVS797B – MARCH 2012 – REVISED OCTOBER 2015

www.ti.com

Feature Description (continued)

Figure 26. Output Voltage Feedback Circuit

8.3.9 Overvoltage Protection

maximum 2.88 V), the on-period of the integrated MOSFET stop immediately, and the MOSFET keeps off until

in Figure 27 is required. Current is injected to the ILIM pin to drive the LM3492HC device to the current limit

Figure 27. External OVP Circuit

8.3.10 Bidirectional Communication Pin

The COMM pin of the LM3492HC device is an open-drain bidirectional I/O pin for interfacing with an external

MCU for the following functions:

•

power-good indication

•

overtemperature indication

•

output current overvoltage and undervoltage indications

•

switching frequency tuning

•

channel 1 disabling

Except for the power good indication and the overtemperature alerts, all data flow through the COMM pin is

serial and is latched by the falling edge of the signal applying to the DIM1 pin, even when channel 1 of the

current regulator is disabled. If the DIM1 pin remains only low or only high, either by an external circuit or by

allowing it to open and pull low internally, data does not flow. Figure 28 and Figure 29 show timing diagrams of

reading and writing a bit from and to the device through the COMM pin.

to the VCC pin. Without this capability, the voltage of the COMM pin remains at zero. The rise time of the output

from the connecting MCU I/O pin is too weak), data may be ready after a longer duration after the falling edge. In

this case, the design requires a longer delay between the falling edge latching and the (input or output) bit.

16

Submit Documentation Feedback

Copyright © 2012–2015, Texas Instruments Incorporated

Product Folder Links: LM3492HC-Q1 LM3492HC