ACT4910QW
Rev 1.0, 15-Sept-2017
The ACT4910 allows for very flexible health checking
routines by allowing the system to manually enable the
uses an analog input multiplexer to select one of six
channels for the A/D conversion. The resulting digital
results are stored in six digital registers. A six to one
multiplexer connects one of the ADC output registers to
the user accessible register map.
10mA
discharge
current
by
setting
the
EN_STR10mASINK bit = 1. In this situation, the system
manually turns the discharge current on and off. The
storage capacitor voltage threshold is still determined
by the HMON_THR register. This function is useful for
checking extremely large capacitor values which need
very long discharge times.
ADC Configuration
The ACT4910 ADC is configured through the I2C
interface. It is enabled and disabled by the EN_ADC
register bit. The ADC has two conversion modes,
manual single-shot conversion and automatic polling
conversion.
V
Storage CapVoltage
VSTR
PG_THR
(Programmable)
Pr ogramm able
Interval Time
Single-Shot Conversion
Configure the IC for single-shot conversion mode by
setting the following I2C bits in register 0x08h
0
t
I
Pr ogramm able
Discharge Time
50mA
ADC_ONE_SHOT = 1.
ADC_CH_SCAN = 0
EN_ADCBUF = 1
200us
Discharge Current
10mA
0
Top-Off
Maintain
t
Health Testing
Initial Charge
In single shot mode, the user defines the input channel
to be converted and then manually initiates the ADC
conversion. I2C bits ADC_CH_CONV [2:0] in register
0x08h select the input channel to be converted.
ADC_CH_READ [2:0] selects the ADC channel to be
read. These should be set to the same channel. The
user initiates an ADC read by writing a 1 into EN_ADC
in register 0x08h. When ADC conversion is complete,
the ADC_DATA_READY bit (register 0x07h [7]) is set to
1, nIRQ is asserted low, and EN_ADC automatically
changes back to 0. The uP can then read the status bits
to find that the ADC conversion is complete. The ADC
data are stored in ADC_DOUT [13:6] in register 0x05h.
nIRQ stays asserted low and the ADC_READY_BIT
stays equal to 1 until the ADC data is read. Reading the
ADC data automatically deasserts nIRQ. To initiate
another ADC conversion for the same channel, set
EN_ADC=1. To initiate an ADC conversion for another
Figure 6: Storage Voltage at Different Stages
The register HMON_TSET [3:0] sets the health check
discharge time as shown in Table 7. This also allows the
use of the ADC to check the slope of the discharge and
calculate the capacitance.
Table 7: Health Check Discharge Time
HMON_TSET[3] (ms)
HMON_TSET[2:0]
0
1
000
001
010
011
100
101
110
111
2
384
512
640
768
896
1024
1152
1280
4
8
16
32
64
128
256
channel,
change
ADC_CH_CONV
and
ADC_CH_READ to the appropriate channel and then
set EN_ADC=1.
ADC Monitoring
General Description
The ACT4910 contains a built-in analog to digital con-
verter, ADC, which can be used to monitor five system
level parameters. These include input voltage, output
voltage, storage capacitor voltage, eFuse current, and
die temperature. It is a single 8 bit delta-sigma ADC that
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