LNBH23

LNBH23 software description

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7.3

Transmitted data (I²C bus write mode)

When the R/W bit in the chip address is set to 0, the main MCU can write on the system

register (SR) of the LNBH23 via I²C bus. All and 8 bits are available and can be written by

the MCU to control the device functions as per the below truth table

X = don't care

All values are typical unless otherwise specified

Valid with TTX pin floating or to GND

7.4

Diagnostic received data (I²C read mode)

LNBH23 can provide to the MCU Master a copy of the diagnostic system register

information via I²C bus in read mode. The read mode is master activated by sending the

chip address with R/W bit set to 1. At the following master generated clocks bits, LNBH23

issues a byte on the SDA data bus line (MSB transmitted first). At the ninth clock bit the

master can:

●

Acknowledge the reception, starting in this way the transmission of another byte from

the LNBH23

●

No acknowledge, stopping the read mode communication

Three bits of the register are read back as a copy of the corresponding write output voltage

register status (LLC, VSEL, EN), while, the other five bits convey diagnostic information

about the over-temperature (OTF), output voltage level (VMON), output over-load (OLF),

Minimum output current presence (IMON) and 22 kHz tone (TMON). In normal operation the

diagnostic bits are set to zero, while, if a failure is occurring, the corresponding bit is set to

one. At start-up all the bits are reset to zero.

Table 6.

Truth table

PCL

TTX

TEN

LLC

VSEL

EN

ITEST

AUX

Function

00

0

1

0

00

1

1

0

01

0

1

0

01

1

1

0

XX

1

X

1

0

1

22 kHz controlled by DSQIN pin (only if TTX=1)

1

1

1

22 kHz tone output is always activated

01

OFF

11

0

1

Pulsed (Dynamic) current limiting is selected

1

1

Static current limiting is selected

XX

1

0

Minimum output current diagnostic threshold = 6mA

typ.

XX

1

1

Minimum output current diagnostic threshold = 12mA

typ.

X

X

X

X

X

0

X

X

Power block disabled