AMC7834 Datasheet, PDF (31/93 Pages) Texas Instruments – AMC7834 12-Bit Integrated Power-Amplifier Monitor and Control System with Temperature, Current and Voltage Supervision Capabilities

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AMC7834
SLAS972B – NOVEMBER 2014 – REVISED MARCH 2016
7.3.2.3 ADC Sequencing
The AMC7834 supports autonomous and direct-mode ADC conversions. The conversion method is selected in
the AMC configuration 0 register (address 0x10). The default conversion method is autonomous conversion. In
both conversion methods, the channel or group of channels to be converted by the ADC must be first configured
in the ADC MUX register (address 0x12). The input channels to the ADC include 4 external inputs, 4 DAC
monitoring internal inputs, 4 current-sense inputs, 2 remote temperature sensor inputs, and the internal
temperature sensor.
The ADC must be in the READY state before a conversion cycle is started. The ADC enters the READY state
once powered-up and at least one input channel is enabled in the ADC MUX register. The ADC READY status
can be determined either through software (ADC-READY bit in the General Status register, 0x1F) or hardware
(DAV/ADC_RDY pin). To use the DAV/ADC_RDY pin as a READY status indicator, the pin must first be enabled
through the DAVPIN-EN bit in register 0x11. Furthermore the ADC_RDY functionality must be selected by setting
the DAVPIN-SEL bit in register 0x11 to '1'.
The conversion cycle is initiated by setting the ADC-TRIG bit to 1 in the DAC and ADC Trigger register (address
0x1C) which issues an ADC trigger signal. If the trigger signal is issued while the ADC is not in the READY state
it is ignored.
Once the conversion cycle starts the ADC leaves the READY state. In direct-mode conversion upon completion
of the first conversion sequence the ADC returns to the READY state and waits for a new trigger signal.
Alternatively, in autonomous conversion upon completion of the first conversion another sequence is
automatically started. Conversion of the selected channels occurs repeatedly until the conversion is stopped by
issuing another trigger signal, at which point the ADC returns to the READY state.
The following ADC registers should only be updated while the ADC is not in a conversion cycle:
• Device configuration register (address 0x02)
• AMC configuration 0 register (address 0x10)
• AMC configuration 1 register (address 0x11)
• ADC MUX register (address 0x12)
• ALARMOUT configuration register (0x1B)
• Threshold registers (0x40 – 0x4D)
• Hysteresis registers (0x50 – 0x56)
After updating any of the configuration registers listed above, either a minimum 2 µs wait time or READY state
must be ensured before issuing an ADC trigger signal.
Since the ADC is used for voltage, current, and temperature sensor conversions, all of which have significantly
different update times, an interleaved conversion sequence is followed. The interleaved sequence ensures the
wait time between measurement updates is minimized. Figure 48 illustrates the ADC conversion sequence with
all input channels enabled and set to their fastest update time (CS-FILTER[2:0] = 000 and RT-SET[2:0] = 000 in
the AMC Configuration register - 0x10).
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