LP3913 Datasheet, PDF (44/70 Pages) Texas Instruments – Power Management IC for Flash Memory-Based Portable Media Players

LP3913
SNVS489I – NOVEMBER 2006 – REVISED SEPTEMBER 2013
ADCC Register (0a)h A/D Converter Control Register
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Access
Data
D7
r/w
V_RANGE
0: 2.6V–3.5V
1: 2.6V–4.4V
D6
r/w
I_RANGE
D5
D4
Read Only
ADC Overflow Data Ready
0: 0 mA–605 mA 0: no overflow 0: no data
1: 0 mA–1100 mA 1: overflow
1: data ready
D3
r/w
Start
Conversion
0: default
1: start
conversion
Reset 0
0
0
0
0
D2
r/w
ADC Enable
0: Disabled
1: Enabled
0
D1–0
ADC source
selection
00: battery voltage
01: battery charge
current
10: ADC1
11: ADC2
0
ADCD Register (0b)h A/D Converter Output Data Register
Charge current 0A to 1.1A mirrored to 0 µA to 250 µA, ADC measures voltage drop across R_SENSE 4.64 kΩ.
Access
Data
Reset
D7–0
Read Only 0
Battery voltage:
8’h00 = 2.6V
8’h00= 2.6V
Battery charge current 8’h00 = 0
8’h00 = 0
ADC1:
ADC2:
8’h00
8’h00 = V_REFH = 1.225V
8’h00 = V_REFH = 1.225V
8’hFF = 2*V_REFH = 2.45 V
8’hFF = 2*V_REFH = 2.45 V
8’hFF = 3.5V 1 LSB = 0.9 / 256 = (3.5
mV) range 0
8’hFF = 4.4V 1 LSB = 1.8 / 256 = (7.0
mV) range 1
8’hFF = 0.6463V = 605 mA range 0
8’hFF = 1.175V = 1100 mA range 1
(1 LSB = V_REFH/256)
(1 LSB = V_REFH/256)
The ADC is by default disabled to minimize current consumption and needs to be enabled by setting D2 in the
ADCC register. Writing a logic 1 to bit D3 in the ADC will initiate a conversion. It is advised to select the correct
ADC source before a conversion is started. The A/D converter will set bit D4 in the ADCC register upon the
completion of a conversion, which is typically 4 ms after the start of the conversion. At the same time an interrupt
request will be generated. (See IRQ Register (0d)h Interrupt Request Register).
To save power, disable the ADC by setting bit 2 of D2 to 0. To make repetitive starts, set bit D3 to 0 then to 1 for
register 0Ah to initiate start of conversion. The interrupt driven protocol between LP3913 and the system
processor is the most efficient way to acquire data from successive measurements:
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