Datasheet

Vdd

BIAS

To ADC Mux

On/Off Control

AD00,

AD01

Resistor to

set PMBus

Address

UCD3138

SLUSAP2F –MARCH 2012 –REVISED NOVEMBER 2013

www.ti.com

Figure 4-6. PMBus Address Detection Method

4.15.3 General Purpose ADC12

The ADC12 is a 12 bit, high speed analog to digital converter, equipped with the following options:

• Typical conversion speed of 267 ksps

• Conversions can consist from 1 to 16 ADC channel conversions in any desired sequence

• Post conversion averaging capability, ranging from 4X, 8X, 16X or 32X samples

• Configurable triggering for ADC conversions from the following sources: firmware, DPWM rising edge,

ADC_EXT_TRIG pin or Analog Comparator results

• Interrupt capability to embedded processor at completion of ADC conversion

• Six digital comparators on the first 6 channels of the conversion sequence using either raw ADC data

or averaged ADC data

• Two 10 µA current sources for excitation of PMBus addressing resistors

• Dual sample and hold for accurate power measurement

• Internal temperature sensor for temperature protection and monitoring

The control module ( ADC12 Contol Block Diagram) contains the control and conversion logic for auto-

sequencing a series of conversions. The sequencing is fully configurable for any combination of 16

possible ADC channels through an analog multiplexer embedded in the ADC12 block. Once converted,

the selected channel value is stored in the result register associated with the sequence number. Input

channels can be sampled in any desired order or programmed to repeat conversions on the same channel

multiple times during a conversion sequence. Selected channel conversions are also stored in the result

registers in order of conversion, where the result 0 register is the first conversion of a 16-channel

sequence and result 15 register is the last conversion of a 16-channel sequence. The number of channels

converted in a sequence can vary from 1 to 16.

Unlike EADC0 through EADC2, which are primarily designed for closing high speed compensation loops,

the ADC12 is not usually used for loop compensation purposes. The EADC converters have a

substantially faster conversion rate, thus making them more attractive for closed loop control. The ADC12

features make it best suited for monitoring and detection of currents, voltages, temperatures and faults.

Please see the Typical Characteristics plots for the temperature variation associated with this function.

Submit Documentation Feedback

Product Folder Links: UCD3138