Intel Pentium 4 Processor VR-Down Design Guidelines
Table Of Contents
- Output Requirements
- Voltage and Current REQUIRED
- Voltage Tolerance REQUIRED
- Load Line Definitions REQUIRED
- Processor Electrical And Thermal Current Support EXPECTED
- No-Load Operation EXPECTED
- Turn-on Response Time PROPOSED
- Processor Power Sequencing REQUIRED
- Overshoot at Turn-On or Turn-Off REQUIRED
- Converter Stability REQUIRED
- Thermal Monitoring PROPOSED
- Input Voltage and Current
- Control Inputs REQUIRED
- Power Good Output (PWRGD) PROPOSED
- Efficiency PROPOSED
- Fault Protection
Intel
®
Pentium
®
4 Processor VR-Down Design Guidelines
16
6 Fault Protection
6.1 Over Voltage Protection EXPECTED
The VR should provide over-voltage protection (OVP) by including a circuit, separate from the voltage
sense path, capable of shutting off the output drive when the output voltage rises beyond Vtrip. If
practical, the protection circuit should also enable a low-resistance path to ground such that if the
output transistor shorts to input power the output voltage will not rise above Vtrip. A non-resettable or
resettable fuse may be included in the input of the VR for this function. The response time should be
such that the output voltage will not exceed the non-operating V
MAX in Table 1 corresponding to the
selected VID.
Minimum Vtrip should be the Maximum Vout specified in Section 1.3 plus margin to prevent false
trips. No combination of input voltage sequences should falsely trigger an OVP event.
6.2 Fuse Protection for Power Input PROPOSED
The power input (12V) should be protected with a fuse rated not greater than 30A, which sustains all
operating and inrush conditions and which “blows” only on catastrophic failure of the converter.
6.3 Overload Protection EXPECTED
The VR should be capable of withstanding a continuous, abnormally low resistance on the output
without damage or over-stress to the unit. Output current under this condition will be limited to no
more than 150% of the maximum rated output of the VR. Latching off or hiccup mode is acceptable
during over-current conditions. The VR should be capable of starting into a constant current load of
50% of maximum rated load current with maximum load capacitance, as defined in Section 1.3,
without tripping the Over Current Protection (OCP) circuitry.
6.4 Reset After Shutdown PROPOSED
If the VR goes into a shutdown state due to a fault condition on its output (not an internal failure) it
should return to normal operation after the fault has been removed, or after the fault has been removed
and power has been cycled off and on.