isppac-powr6at6 Lattice Semiconductor Corp., isppac-powr6at6 Datasheet - Page 10

• Manufacturer Part Number: isppac-powr6at6
• Description: In-system Programmable Power Supply Monitoring And Margining Controller
• Manufacturer: Lattice Semiconductor Corp.

Lattice Semiconductor
Theory of Operation
Voltage Measurement with the On-chip Analog to Digital Converter (ADC)
The ispPAC-POWR6AT6 has an on-chip analog to digital converter that can be used for measuring the voltages at
the VMON inputs. The ADC is also used in closed loop trimming of DC-DC converters. Close loop trimming is cov-
ered later in this document.
Figure 6. ADC Monitoring VMON1 to VMON6
Figure 6 shows the ADC circuit arrangement within the ispPAC-POWR6AT6 device. The ADC can measure all ana-
log input voltages through the multiplexer, ADC MUX. The programmable attenuator between the ADC mux and
VMON pins can be configured as divided-by-3 or divided-by-1 (no attenuation). The divided-by-3 setting is used to
measure voltages from 0V to 6V range and divided-by-1 setting is used to measure the voltages from 0V to 2V
range.
A microcontroller can place a request for any VMON voltage measurement at any time through the I
the receipt of an I
ADC output is then latched into the I
VMON 1
VMON 2
VMON 3
VMON 4
VMON 5
VMON 6
2
C command, the ADC will be connected to the I
+
+
+
+
+
+
–
–
–
–
–
–
Programmable
Attenuator
÷3 / ÷1
÷3 / ÷1
÷3 / ÷1
÷3 / ÷1
÷3 / ÷1
÷3 / ÷1
2
C readout registers.
From Closed
Loop Trim
Circuit
ADC
MUX
3
10
ADC MUX
From I
Address
2
C
2
C selected VMON through the ADC MUX. The
ADC
Internal
2.048V
VREF-
ispPAC-POWR6AT6 Data Sheet
10
To Closed
Loop Trim
Register
Readout
Circuit
To I
2
C
2
C bus. Upon