LP3941A Datasheet, PDF (20/32 Pages) National Semiconductor (TI) – Cellular Phone Power Management Unit

LP3941A Serial Port Communication Address Code 7h’7E (Continued)
TABLE 1. LP3941 Control and Data Codes (Continued)
Note 14: Register h’0d stores the status of ON, RTC_ALARM, CHG_IN and HF_PWR inputs at the time of PMIC power on event. The bits indicate why the device
turned on, and are static after the power on incident.
ON = 1 means the ON-input was logic high at the moment of power-up-sequence start.
RTC_ALARM = 1 indicates that RTC_ALARM-input was logic high when the power-up-sequence started.
CHG_IN = 1 indicates that external battery charger initiated the power-up-sequence. This also implies that the battery is connected (BSNS = 0V) and that battery
voltage is over 3.0V, because otherwise the circuit will not power up.
HF_POWER = 1 indicates HF_PWR was logic high when the power-up-sequence started.
0 in any register bit position means that the corresponding signal did not initiate the power-up sequence.
Multiple bits can be ‘1’ at the same time if they simultaneously initiated the power-up-sequence.
Note 15: Register h’2e shows the current status of comparator outputs, ADC block, ON-, RTC_ALARM and HF_PWR-inputs. Bit 3 of the register indicates if a valid
external battery charger is connected to the LP3941 at the moment. Register h’2e is dynamic and shows the current status of these variables at all times.
COMP1/2 OUT = 1 means the corresponding comparator input is > threshold (see comparator specification).
ON, RTC_ALARM, HF_PWR = 1 indicates corresponding input pins are logic high.
CHARGER_PRESENT means CHG_IN pin has valid voltage for charging. (See charger specification.)
Note 16: For description on the operation of ADC Overflow and ADC Data Ready bits please see ADC specifications.
Regulator Output Voltage Programming
The following table summarizes the supported output voltages for LP3941A. Default voltages after start-up sequence have been
highlighted in bold.
Data Code
V_O1
V_O2
V_O3
V_O4
V_O5
V_O6
V_O7
V_O8
V_O9
V_O10
V_O11
(V)
(V)
(V)
(V)
(V)
(V)
(V)
(V)
(V)
(V)
(V)
4h'00
1.5
1.5
2.5
1.5
2.5
2.5
2.5
2.5
1.5
1.5
1.8
4h'01
1.6
1.6
2.6
1.6
2.6
2.6
2.6
2.6
1.6
1.6
1.9
4h'02
1.7
1.7
2.7
1.7
2.7
2.7
2.7
2.7
1.7
1.7
2.0
4h'03
1.8
1.8
2.8
1.8
2.8
2.8
2.8
2.8
1.8
1.8
2.1
4h'04
1.9
1.9
2.9
1.9
2.9
2.9
2.9
2.9
1.9
1.9
2.2
4h'05
2.0
2.0
3.0
2.0
3.0
3.0
3.0
3.0
2.0
2.0
2.3
4h'06
2.1
2.1
3.1
2.1
3.1
3.1
3.1
3.1
2.1
2.1
2.4
4h'07
2.2
2.2
3.2
2.2
3.2
3.2
3.2
3.2
2.2
2.2
2.5
4h'08
2.3
2.3
2.3
2.3
2.3
2.6
4h'09
2.4
2.4
2.4
2.4
2.4
2.7
4h'0a
2.5
2.5
2.5
2.5
2.5
2.8
4h'0b
2.6
2.6
2.6
2.6
2.6
2.9
4h'0c
2.7
2.7
2.7
2.7
2.7
3.0
4h'0d
2.8
2.8
2.8
2.8
2.8
3.1
4h'0e
2.9
2.9
2.9
2.9
2.9
3.2
4h'0f
3.0
3.0
3.0
3.0
3.0
3.3
Register Programming Examples
Example 1. Setting register h’00 value to 8h’ff’ will enable
LDOs 1–8.
Example 2. Setting register h’01 to 8h’8c’ will set LDO9
output to 2.3V and LDO1 output to 2.7V. These voltages will
appear at the LDO outputs if the corresponding LDOs have
been enabled. Programming a voltage value to a LDO,
which is off, will affect the LDO output voltage after the LDO
is enabled. Enabling and programming the output voltage
are separate operations.
Example 3. Setting register h’09 bit ‘0’ to ‘1’ will disable the
main battery charger. Note that all register bits have to be
programmed together. It is not possible to program individual
bits alone. Writing into read only or unused bit positions does
not affect those bits nor does it cause errors. Therefore to
disable the main charger and to retain other bits in their
default values on would write 8h‘03’
ADC and Charger Programming
The following tables show how to select the main battery
charger End-Of-Charge current limit, how to set the charger
current limit and select a particular input for ADC measure-
ment. Default values have been highlighted in bold.
SEL-1
0
1
1
EOC Current Selection Code
SEL-0
1
I_SET (mA)
0.1C
0
0.15C
1
0.2C
MUX-1
0
0
1
A/D Input Selection Code
MUX-0
Input
0
V_BATT
1
I_CHG
0
BATT-ID (20 µA Scale)
www.national.com
20