ZM7304G-65503Y-Q1 POWER-ONE [Power-One], ZM7304G-65503Y-Q1 Datasheet - Page 26

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

The ACFAIL_N and RES_N inputs should be controlled with open collector devices. The propagation delay
between the external device pulling the input low and the DPM pulling down OK lines and triggering the turn-off
process is approximately 1ms.
10.6.2 Front End Enable
The FE_EN pin is dedicated to the control of a DC-DC Front End. The Front End is typically used to convert the
48V into the intermediate bus voltage (IBV). If the DPM is powered from an auxiliary source, not from the IBV, it
can control the DC-DC Front End.
When FE_EN is internally pulled up to 3.3V, the Front End is enabled. The FE_EN output can provide up to 5mA
of current. When the FE_EN goes low, the Front End is disabled. The Front End can be enabled and disabled via
the GUI IBS Monitoring Window or directly via the I
The FE_EN pin should not be directly connected to the Enable pin of the DC-DC Front End. Typically, the Enable
pin is referenced to the primary side of the Front End that is isolated from the low voltage secondary side. In
addition, the Enable pin can be pulled up internally to a voltage potentially damaging to the DPM FE_EN output.
The best method is to interface the DPM with the Front End through an optocoupler as shown in Figure 20. This
configuration provides interface for negative logic front ends.
10.6.3 Crowbar
When the crowbar protection is enabled, the CB pin is internally pulled up to 3.3V for 1ms. It is capable of
supplying 5mA to turn on a crowbar circuit.
10.6.4 HRES_N
The HRES_N is an active low digital input. When it is pulled low, the DPM will perform full hardware reset
including processor, memory, and communication interface. The POL converters and auxiliary devices will be
turned off although sequencing and tracking during the turn-off are not guaranteed. Communication with a host
processor or GUI (if established) will be lost. When the input is released, the DPM will first program all POL
converters and then turn them on, if the Auto Turn-On is enabled.
The HRES_N should not be used during normal system operation. It is intended to be an emergency reset and
should only be used as such.
REV. 3.3 NOV 26, 2007
FE_EN
Figure 20. Interface Between DPM and DC-DC Front End
DPM
GND
www.power-one.com
3.3k
R
R
2
C bus using specific commands.
Q
ZM7300G Series Digital Power Manager
Enable
-VIN
Front End
Page 26 of 32
Data Sheet