ALED7709ATR datasheet(34/63 Pages) STMICROELECTRONICS

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7.14

Table of different working modes

Table 15. DIMCFG bit settings for different working modes

DIMCFG bits setting

Mode

Notes

Reg_PWMI = 0

(PWMI control; acts

as PWM1 global)

FDIM[2:0] = xxx

(Dimming frequency

depends on PWMI

signal)

GLDM = 0

(GLOBAL; GAIN1 is

global)

UMDM = 0 (USER;

GAIN1 can be

modified by Reg)

PWM_DRCT = 0

LECC = 0

LECC = 1

PWMI_DRCT = 1

LECC = x

In PWMI direct

control, linear

and exponential

conversion have no

meaning

UMDM = 1 (MIXED;

GAIN1 is controlled

by PWMI)

PWMI_DRCT = 0

LECC = 0

In mixed mode only

global dimming is

possible

LECC = 1

GLDM = 1 (LOCAL;

GAINx are active)

UMDM = 0 (LOCAL

can be only USER;

GAINx can be

modified by Reg)

PWM_DRCT = 0

LECC = 0

LECC = 1

PWMI_DRCT = 1

LECC = x

In PWMI direct

control, linear

and exponential

conversion have no

meaning

Reg_PWMI = 1

(Register control;

PWM and GAIN

are fully adjustable

depending on

other bit settings)

FDIM[2:0] = SET

(Dimming frequency

is defined by Reg

value)

GLDM = 0

(GLOBAL; PWM1

and GAIN1 are

global)

UMDM = 0 (USER;

PWM1 and GAIN1

can be modified by

Reg)

PWMI_DRCT = x

LECC = 0

LECC = 1

M10

UMDM = 1 (MIXED;

PWM1 value acts

as Bright and

control both Digital

and Analog output

values)

LECC = 0

M11

In mixed mode only

global dimming is

possible

LECC = 1

M12

GLDM = 1 (LOCAL;

PWMx and GAINx

are active and fully

independent)

UMDM = 0 (LOCAL

can be only USER;

PWMx and GAINx

can be modified by

Reg)

LECC = 0

M13

LECC = 1

M14

Following the description of each working mode, the value of DIMCFG to set the corresponding working mode is

reported in the section title. The value is in binary, the bits written as “x” mean “don’t care”, the ones written as “X”

mean “customer setting”, this is mainly related to FDIM[2:0] bits.

7.14.1

Working mode M1 (Reg DIMCFG = 00xxx000b)

PWMI is sampled to recover duty-cycle and frequency to be applied to all the outputs; frequency is set as for

Table 13 while duty-cycle sets the output pulse duration following the linear curve.

All the outputs go to OFF if the PWMI signal stays at LOW level for more than 20 ms.

Current is set for all the channels by the register GAIN1 value.

7.14.2

Working mode M2 (Reg DIMCFG = 00xxx100b)

PWMI is sampled to recover duty-cycle and frequency to be applied to all the outputs; frequency is set as for

Table 13 while duty-cycle sets the output pulse duration following the exponential curve.

All the outputs go to OFF if the PWMI signal stays at LOW level for more than 20 ms.

Current is set for all the channels by the register GAIN1 value.

ALED7709

Table of different working modes

DS14214 - Rev 1

page 34/63

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