L6611 Datasheet, PDF(16/28 Page) STMicroelectronics – DIGITALLY PROGRAMMABLE SECONDARY HOUSEKEEPING CONTROLLER

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L6611 Datasheet, PDF (16/28 Pages) STMicroelectronics – DIGITALLY PROGRAMMABLE SECONDARY HOUSEKEEPING CONTROLLER

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L6611

APPLICATION INFORMATION

1 ONBOARD DIGITAL TRIMMING AND MODE SELECTION

By forcing the PROG input pin high, the chip enters programming mode: the multifunction pins PW_OK and

PS_ON are then disconnected from their normal functions (output pins) and are connected to internal logic as

DATA and CLOCK inputs respectively, allowing chip programming even when the device is assembled on the

application board. Onboard chip programming allows:

â selecting some working options;

â reference voltage setpoints adjusting.

It is also possible to verify the expected results before programming the chip definitively, in first instance, data

can be loaded into a re-writeble volatile memory (a flip-flop array) where they are kept as long as the chip is

supplied and can be changed as many times as one desires. A further operation is necessary to confirm the

loaded data and permanently store them into a PROM (a poly-fuse array) inside the IC.

Several steps compose the trimming/programming process:

1. PROG pin is forced high;

2. a clock signal is sent to the PS-ON/clock pin;

3. a byte with the following structure:

MSB

LSB

Data

Address

is serially sent to the PW-OK/DATA pin and loaded into the IC's volatile memory bit by bit on the falling edges

of the clock signal (see Fig. 14); "Address" is the identification code of the parameter that has to be trimmed

and "Data" contains the tuning bits;

4. PROG pin is forced low (warning: Vdd must never fall below VddUVL0 during this process otherwise the con-

tents of the volatile memory will be lost) and the result of the previous step is checked;

5. after any iterations of the steps 1-4 that might be necessary to achieve the desired value, force PROG pin

high and send the following burn code

MSB

LSB

to permanently store the data in the PROM memory.

Table 1 shows the list of the 6 programmable classes of functions, each one identified by a different code

A0..A3, and the corresponding trimmable parameter(s); in table 2 it is possible to find the trim coding for the E/

A reference setpoints and in table 3 all the selections mode option coding are showed. The timing diagram of

fig. 14 shows the details of data acquisition.

Table 1. Programmable functions

Address

Parameter(s)

0001

Error amplifier A threshold

0010

Error amplifier B threshold

0011

Error amplifier C threshold

0100

AC sense threshold

0101

AC sense hysteresis

Latch/Bounce mode selection

Enable/Disable 12V UV/OV function

0110

Enable/Disable 5V UV/OV function

5V/3V3 Dmon selection

Default value

2.50V

1.25V

2.50V

50ÂµA

Latch mode

Enabled

5V selection

Tuning bits

D3 D2 D1 DO

D2 D1 DO

donât care

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