34704 datasheet(24/54 Pages) FREESCALE

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Analog Integrated Circuit Device Data

Freescale Semiconductor

34704

FUNCTIONAL DESCRIPTION

FUNCTIONAL INTERNAL BLOCK DESCRIPTION

• The output is monitored for over-current and short-circuit

conditions

• The regulator is monitored for over-temperature conditions

Operation Modes

The switcher will be active when:

• VG is in regulation AND

• There is no GrpC (OR GrpE) shutdown command through

the I2C interface AND

• No faults exist that would cause GrpC (OR GrpE) to shut

down

REG6 (Only 34704A)

This is a synchronous boost PWM voltage-mode control

DC/DC regulator.

See Power-Up Sequence on page 28 for more details on

when REG6 is powered up in the sequence.

The switcher will operate in DCM at very light loads to

allow pulse skipping.

VOUT6 will be discharged every time the regulator is

shutting down and it will be held low by the discharge FET as

long as possible.

Characteristics

• It powers up directly from the battery

• Operates at a switching frequency equals to FSW2

• Drives integrated low RDS(ON) N-channel power

MOSFETs (NVHV_LC) as its output stage

• It offers load disconnect from the input battery when the

output is off (True Cut-Off)

• The output is ±4% accuracy

• Output voltage is adjustable by means of an internal

resistor divider

• The output can be adjusted up or down at 2.5% steps for

a total of 10% on each direction allowing Dynamic Voltage

Scaling

• Uses a bootstrap network with an internal diode to power

its synchronous MOSFET

• All gate drive circuits are supplied from VG.

• Uses integrated compensation.

• The output is monitored for under-voltage and over-

voltage conditions

• The output is monitored for over-current and short-circuit

conditions

• The regulator is monitored for over-temperature conditions

Operation Modes

The switcher will be active when:

• VG is in regulation AND

• There is no GrpC shutdown command through the I2C

interface AND

• No faults exist that would cause GrpC to shut down

REG7 (Only 34704A)

This is a none-synchronous buck-boost inverting PWM

voltage-mode control DC/DC regulator.

See Power-Up Sequence on page 28 for more details on

when REG7 is powered up in the sequence.

The switcher will operate in DCM at very light loads to

allow pulse skipping.

VOUT7 will be discharged every time the regulator is

shutting down and it will be held high to ground by the

discharge FET as long as possible.

Characteristics

• It powers up directly from the battery

• Operates at a switching frequency equals to FSW2

• Drives an external P-channel power MOSFET

• The output is ±2% accuracy

• Output voltage is adjustable by means of an external

resistor divider

• The output can be adjusted up or down at 2.5% steps for

a total of 10% on each direction allowing Dynamic Voltage

Scaling.

• All gate drive circuits are supplied from VG

• Uses external compensation, the type is up to the designer

• The output is monitored for under-voltage and over-

voltage conditions

Operation Modes

The switcher will be active when:

• VG is in regulation AND

• There is no GrpC shutdown command through the I2C

interface AND

• No faults exist that would cause GrpC to shut down

REG8

This is a synchronous boost PWM voltage-mode control

DC/DC regulator.

See Power-Up Sequence on page 28 for more details on

when REG8 is powered up in the sequence.

VOUT8 will be discharged every time the regulator is

shutting down and it will be held to ground by the discharge

FET as long as possible.

This regulator offers either voltage regulation for organic

LEDs or current regulation for LCD backlighting LEDs. It

provides either voltage or current feedback for these

purposes through the same feedback pin.

The regulator cannot drive only 1LED with a forward

voltage drop of less than the battery input voltage.

The processor would set the REG8 register through I2C

before enabling REG8 to indicate if voltage regulation or

current regulation will be used.

Characteristics

• It powers up directly from the battery

34704 Datasheet(PDF) 24 Page - Freescale Semiconductor, Inc

34704 Datasheet(HTML) 24 Page - Freescale Semiconductor, Inc

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