ZL2006 Datasheet, PDF (32/45 Pages) Intersil Corporation – Adaptive Digital DC-DC Controller with Drivers and Current Sharing

ZL2006
6.4 Output Overcurrent Protection
The ZL2006 can protect the power supply from
damage if the output is shorted to ground or if an
overload condition is imposed on the output. Once the
current limit threshold has been selected (see Section
5.9 “Current Limit Threshold Selection”), the user may
determine the desired course of action in response to
the fault condition. The following overcurrent
protection response options are available:
1. Initiate a shutdown and attempt to restart an
infinite number of times with a preset delay period
between attempts.
2. Initiate a shutdown and attempt to restart a preset
number of times with a preset delay period
between attempts.
3. Continue operating for a given delay period,
followed by shutdown if the fault still exists.
4. Continue operating through the fault (this could
result in permanent damage to the power supply).
5. Initiate an immediate shutdown.
The default response from an overcurrent fault is an
immediate shutdown of the device. The device will
continuously check for the presence of the fault
condition, and if the fault condition no longer exists the
device will be re-enabled.
Please refer to Application Note AN33 for details on
how to select specific overcurrent fault response
options via I²C/SMBus.
6.5 Thermal Overload Protection
The ZL2006 includes an on-chip thermal sensor that
continuously measures the internal temperature of the
die and shuts down the device when the temperature
exceeds the preset limit. The default temperature limit
is set to 125°C in the factory, but the user may set the
limit to a different value if desired. See Application
Note AN33 for details. Note that setting a higher
thermal limit via the I²C/SMBus interface may result in
permanent damage to the device. Once the device has
been disabled due to an internal temperature fault, the
user may select one of several fault response options as
follows:
1. Initiate a shutdown and attempt to restart an
infinite number of times with a preset delay period
between attempts.
2. Initiate a shutdown and attempt to restart a preset
number of times with a preset delay period
between attempts.
3. Continue operating for a given delay period,
followed by shutdown if the fault still exists.
4. Continue operating through the fault (this could
result in permanent damage to the power supply).
5. Initiate an immediate shutdown.
If the user has configured the device to restart, the
device will wait the preset delay period (if configured
to do so) and will then check the device temperature. If
the temperature has dropped below a threshold that is
approx 15°C lower than the selected temperature fault
limit, the device will attempt to re-start. If the
temperature still exceeds the fault limit the device will
wait the preset delay period and retry again.
The default response from a temperature fault is an
immediate shutdown of the device. The device will
continuously check for the fault condition, and once
the fault has cleared the ZL2006 will be re-enabled.
Please refer to Application Note AN33 for details on
how to select specific temperature fault response
options via I²C/SMBus.
6.6 Voltage Tracking
Numerous high performance systems place stringent
demands on the order in which the power supply
voltages are turned on. This is particularly true when
powering FPGAs, ASICs, and other advanced
processor devices that require multiple supply voltages
to power a single die. In most cases, the I/O interface
operates at a higher voltage than the core and therefore
the core supply voltage must not exceed the I/O supply
voltage according to the manufacturers' specifications.
Voltage tracking protects these sensitive ICs by
limiting the differential voltage between multiple
power supplies during the power-up and power down
sequence. The ZL2006 integrates a lossless tracking
scheme that allows its output to track a voltage that is
applied to the VTRK pin with no external components
required. The VTRK pin is an analog input that, when
tracking mode is enabled, configures the voltage
applied to the VTRK pin to act as a reference for the
device’s output regulation.
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Data Sheet Revision 2/18/2009
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