ZM7304G-65503Y-Q1 POWER-ONE [Power-One], ZM7304G-65503Y-Q1 Datasheet - Page 19

• Manufacturer Part Number: ZM7304G-65503Y-Q1
• Description: Digital Power Manager
• Manufacturer: POWER-ONE [Power-One]

ZM7300G Series Digital Power Manager
Data Sheet
the hysteresis, the DPM will first program all POL converters and then turn them on, if the Auto Turn-On is enabled
in the POL Group configuration window shown in Figure 10. Otherwise, the user will need to send the turn-on
2
command via the I
C bus.
When the IBV exceeds the IBH threshold plus the hysteresis, the DPM will pull OK lines low turning off all POL
converters. The POL converters will execute regular turn-off ramping their output voltages down according to the
turn-off delay and falling slew rate settings. In addition, the DPM will save the contents of the Run Time Counter
into the non-volatile memory. If the IBV does not decrease below the IBH threshold minus the hysteresis within
the next 50ms, the DPM will pull low the FE_EN output and clear all bits in the POL Programming Status registers.
The IBV High bit in the IBS Monitoring Window will change to red. If the IBV still does not change, in 50ms the
DPM will pull the CB pin high for 1ms to trigger an optional crowbar protection.
One second after the IBV decreases below the IBH threshold minus the hysteresis, the DPM will pull the FE_EN
high and program all POL converters. Upon completion of the programming process, the DPM will turn on the
POL converters, if the Auto Turn-On is enabled in the POL Group configuration window shown in Figure 10.
The propagation delay between the IBV increasing/decreasing above/below corresponding thresholds and the
DPM pulling down OK lines and triggering the turn-off process is approximately 1ms.
10.4.4.1
Voltage Reference
For the purposes of IBV monitoring the user can select either the DPM’s internal voltage reference or an external
2.5V voltage reference. The selection is made by clicking an appropriate radio button in the DPM Type Selection
window shown in Figure 14.
Figure 14. DPM Type Selection Window
The DPM’s internal 2.56V voltage reference guarantees 10% overall accuracy of the IBV protection thresholds. If
the accuracy is sufficient, the user does not need to make any changes to the schematic shown in Figure 3. If
higher accuracy of the IBV monitoring is desired, then a 2.5V external reference can be added as shown in Figure
REV. 3.3 NOV 26, 2007
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