MC34704 FREESCALE [Freescale Semiconductor, Inc], MC34704 Datasheet - Page 31

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

Dynamic Voltage Scaling for each regulator
dynamically with 2.5% step size. The total range of
adjustability will vary depending on each regulator to
accommodate different operating environments. Some
regulators will utilize the full range of -20.00% to +17.50%
and some regulators will only use the range of 10.00%. For
details, see each regulator’s section. Each 2.5% step takes
50 s before moving to the next step. REG8 only performs
DVS when in voltage regulation mode.
monitoring will not be active. In addition to that, these faults
will be masked and not active for a DVS settling time period
equal to 1ms. This DVS settling time will start after the
DVSSTAT register is flagged indicating that the DVS cycle is
done. This is to ensure that during DVS and soft start alike
the output will not be tripped due to a momentary over-
voltage or under-voltage fault. This is the same for Response
A and Response B of the over-voltage/under-voltage fault
monitoring.
Voltage Scaling for each regulator ( DVSSETx Register )
where x corresponds to each regulator.
Analog Integrated Circuit Device Data
Freescale Semiconductor
The customer can adjust each regulator’s output
During DVS, the Over-voltage and Under-voltage
34704 assigns a 4-bit register to program the Dynamic
Percentage Change
0.00% (Default)
+10.00%
+12.50%
+15.00%
+17.50%
-20.00%
-17.50%
-15.00%
-12.50%
-10.00%
+2.50%
+5.00%
+7.50%
-7.50%
-5.00%
-2.50%
OV/UV Response
A (Default)
B
MSB
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
bit
0
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
LSB
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
On/Off Control for each group of regulators as defined
previously and for the whole IC
group on/off (ONOFFA, C, D, or E register). Please note that
GrpB does not have a dedicated enable register which is
enabled by default.
IC through the I
Soft Start Time
all of the regulators except REG1. The SSTIME register
reads the soft start value set by the SS pin and is used to
initially set the soft start value for all of the regulators except
REG1. Then, the SSSET registers for REG5 through REG8
can be used to change the soft start value for these
regulators from the value set by the SSTIME register.
SSSETx register:
programmed by the SS pin. The register is called SSTIME
And can only be read by the user.
program the soft start times for these regulators ( SSSETx
register ) where x corresponds to each regulator from REG5
through REG8.
1. SSTIME register is set by a value read through the SS
2. SSTIME register is copied into the registers SSSET5,
3. The soft start time of REG2, REG3, and REG4 are only
4. The soft start time of REG5, REG6, REG7, and REG8
34704 assigns a 1-bit register for each group to turn each
Also, 34704 assigns a 1-bit register for disabling the whole
There are two registers for setting the soft start value for
Here is how the SSTIME register interacts with the
34704 assigns a 2-bit register to store the value
34704 assigns a 2-bit register for REG5 through REG8 to
pin.
SSSET6, SSSET7, and SSSET8.
affected by the value of SSTIME register.
are affected by the value of registers SSSET5,
SSSET6, SSSET7, and SSSET8 respectively.
GrpA, C, D, or E ONOFF
2
Soft Start
C. ( ALLOFF register )
0.5ms
32ms
2ms
8ms
False (Default)
OFF (Default)
ALL OFF
LOGIC COMMANDS AND REGISTERS
True
ON
FUNCTIONAL DEVICE OPERATION
MSB
0
0
1
1
bit
0
1
bit
LSB
0
1
0
1
0
1
34704
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