MC34704 FREESCALE [Freescale Semiconductor, Inc], MC34704 Datasheet - Page 24

• Manufacturer Part Number: MC34704
• Description: Multiple Channel DC-DC Power Management IC
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

24
Operation Modes
• VG is in regulation AND
• There is no GrpC (OR GrpE) shutdown command through
• No faults exist that would cause GrpC (OR GrpE) to shut
REG6 (Only 34704A)
DC/DC regulator.
when REG6 is powered up in the sequence.
allow pulse skipping.
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 F
• Drives integrated low R
• It offers load disconnect from the input battery when the
• The output is ±4% accuracy
• Output voltage is adjustable by means of an internal
• The output can be adjusted up or down at 2.5% steps for
• Uses a bootstrap network with an internal diode to power
• All gate drive circuits are supplied from VG.
• Uses integrated compensation.
• The output is monitored for under-voltage and over-
• The output is monitored for over-current and short-circuit
• The regulator is monitored for over-temperature conditions
Operation Modes
• VG is in regulation AND
• There is no GrpC shutdown command through the I
• No faults exist that would cause GrpC to shut down
REG7 (Only 34704A)
voltage-mode control DC/DC regulator.
when REG7 is powered up in the sequence.
34704
FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
The switcher will be active when:
the I
down
This is a synchronous boost PWM voltage-mode control
See Power-Up Sequence on page 27
The switcher will operate in DCM at very light loads to
VOUT6 will be discharged every time the regulator is
MOSFETs (NVHV_LC) as its output stage
output is off (True Cut-Off)
resistor divider
a total of 10% on each direction allowing Dynamic Voltage
Scaling
its synchronous MOSFET
voltage conditions
conditions
The switcher will be active when:
interface AND
This is a none-synchronous buck-boost inverting PWM
See Power-Up Sequence on page 27
2
C interface AND
DS(ON)
N-channel power
for more details on
for more details on
SW2
2
C
allow pulse skipping.
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 F
• Drives an external P-channel power MOSFET
• The output is ±2% accuracy
• Output voltage is adjustable by means of an external
• The output can be adjusted up or down at 2.5% steps for
• All gate drive circuits are supplied from V
• Uses external compensation, the type is up to the designer
• The output is monitored for under-voltage and over-
Operation Modes
• VG is in regulation AND
• There is no GrpC shutdown command through the I
• No faults exist that would cause GrpC to shut down
REG8
DC/DC regulator.
when REG8 is powered up in the sequence.
shutting down and it will be held to ground by the discharge
FET as long as possible.
LEDs or current regulation for LCD backlighting LEDs. It
provides either voltage or current feedback for these
purposes through the same feedback pin.
voltage drop of less than the battery input voltage.
before enabling REG8 to indicate if voltage regulation or
current regulation will be used.
Characteristics
• It powers up directly from the battery
• Operates at a switching frequency equals to F
• Drives integrated low R
• It offers load disconnect from the input battery when the
• The output is ±4% accuracy
The switcher will operate in DCM at very light loads to
VOUT7 will be discharged every time the regulator is
resistor divider
a total of 10% on each direction allowing Dynamic Voltage
Scaling.
voltage conditions
The switcher will be active when:
interface AND
This is a synchronous boost PWM voltage-mode control
See Power-Up Sequence on page 27
VOUT8 will be discharged every time the regulator is
This regulator offers either voltage regulation for organic
The regulator cannot drive only 1LED with a forward
The processor would set the REG8 register through I
MOSFETs (NVHV_LC) as its output stage
output is off (True Cut-Off)
Analog Integrated Circuit Device Data
DS(ON)
N-channel power
Freescale Semiconductor
for more details on
G
SW2
SW2
2
C
2
C