TDA4841 datasheet(38/60 Pages) PHILIPS

38 / 60 page

1999 Oct 25

Philips Semiconductors

Product speciﬁcation

I2C-bus autosync deﬂection controller for

PC monitors

TDA4841PS

Start-up procedure

VCC < 8.3 V:

• As long as the supply voltage is too low for correct

operation, the IC will give no acknowledge due to

internal Power-On Reset (POR)

• Supply current is 9 mA or less.

VCC > 8.3 V:

• Internal POR has ended and the IC is in standby mode

• Control bits STDBY and SOFTST are reset to their start

values

• All other register contents are random

• Pin HUNLOCK is at HIGH-level.

Setting control bit STDBY = 0:

• Enables internal power supply

• Supply current increases from 9 to 70 mA

• When VCC < 8.6 V register SOFTST cannot be set by

the I2C-bus

• Output stages are disabled

• Pin HUNLOCK is at HIGH-level.

Setting all registers to defined values:

• Due to the hardware configuration of the IC

(no auto-increment) any register setting needs a

complete 3-byte I2C-bus data transfer as follows:

START - IC address - subaddress - data - STOP.

Setting control bit SOFTST = 1:

• Before enabling the soft-start sequence a delay of

minimum 80 ms is necessary to obtain correct function

of the horizontal drive

• HDRV duty cycle increases

• BDRV duty cycle increases

• VOUT1 and VOUT2 are enabled

• PLL1 and PLL2 are enabled.

IC in full operation:

• Pin HUNLOCK is at LOW-level when PLL1 is locked

• Any change of the register content will result in an

immediate change of the output behaviour

• Setting control bit SOFTST = 0 is the only way (except

power-down via pin VCC) to leave the operating mode.

Soft-down sequence:

• See L4 of Fig.19 for starting the soft-down sequence.

Fig.18 I2C-bus flow for start-up.

(1) See Fig.19.

MGL791

START

Standby mode (XXXX XX01)

STDBY = 1

SOFTST = 0

all other register contents are random

Protection mode (XXXX XX00)

STDBY = 0

SOFTST = 0

all other register contents are random

Protection mode (XXXX XX00)

STDBY = 0

SOFTST = 0

registers are pre-set

change/refresh of data?

8CH

1AH

00H

A P

8CH

1AH

02H

A P

8CH

SAD

DATA

A P

8CH

SAD

DATA

A P

Operating mode (XXXX XX10)

STDBY = 0

SOFTST = 1

Soft-start sequence (XXXX XX10)

STDBY = 0

SOFTST = 1

Power-down mode (XXXX XXXX)

no acknowledge is given by IC

all register contents are random

L4 (1)

VCC > 8.3 V

yes

SOFTST = 0?

yes

all registers defined?

yes

TDA4841 Datasheet(PDF) 38 Page - NXP Semiconductors

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