AS3715 datasheet(119/159 Pages) AMSOSRAM

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[v1-03] 2015-Aug-10

AS3715 − Register Description

Figure 137:

Stepup_control4

Note(s) and/or Footnote(s):

1. Step_up switched ON all the time. (current sinks are not switched OFF (currX_on=1 all the time), but currX_current masked to 00h

during PWM low time.). During PWM OFF-time then feedback voltage is sampled.

Figure 138:

Stepup_control5

Addr:53h

Stepup_control4

Bit

Bit Name

Default

Access

Bit Description

stepup2_pwm_lowf

Selects PWM operation of Stepup2

0 : High frequency operation PWM>20kHz.(1)

1 : Low frequency PWM operation: Stepup2_on and

curr1..3_on (if PWM enabled) switched OFF during

PWM low time

stepup2_prot_dis

DCDC converter 2 overvoltage protection to prevent

damage of external NFET,

if CURR1, CURR2 or CURR3 feedback selected, and no

LED string connected

0 : Switch OFF DCDC step up 2 if the voltage on

FB_SU exceeds 1.25V

1 : Overvoltage protection disabled.

1:0

stepup2_fb

b00

RW_SM

Controls the feedback source

0 : FB_SU enabled ( external resistor divider)

1 : CURR1 feedback enabled (feedback through white

LEDs)

2 : CURR2 feedback enabled (feedback through white

LEDs)

3 : CURR3 feedback enabled (feedback through white

LEDs)

Addr:54h

Stepup_control5

Bit

Bit Name

Default

Access

Bit Description

stepup2_clkinv

Invert input clock of step up2 converter

0 : Use positive edge of internal clk

1 : Use negative edge of internal clk

3stepup2_pwm_mode

Enable PWM mode

0 : Normal operation

1 : PWM mode operation. Feedback is sampled

during PWM offtime, if stepup2_lowf=0.

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