HIP6301EVAL2 Intersil, HIP6301EVAL2 Datasheet - Page 10

• Manufacturer Part Number: HIP6301EVAL2
• Description: EVALUATION BOARD HIP6301
• Manufacturer: Intersil

Specifications of HIP6301EVAL2

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 1.6V
• Current - Output: 54A
• Voltage - Input: 5V, 12V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: HIP6301
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -
• Frequency - Switching: -

Fault Protection
The HIP6301 protects the microprocessor and the entire
power system from damaging stress levels. Within the
HIP6301 both Overvoltage and Overcurrent circuits are
incorporated to protect the load and regulator.
Overvoltage
The VSEN pin is connected to the microprocessor CORE
voltage. A CORE overvoltage condition is detected when the
VSEN pin goes more than 15% above the programmed VID
level.
The overvoltage condition is latched, disabling normal PWM
operation, and causing PGOOD to go low. The latch can
only be reset by lowering and returning V
POR and Soft-Start sequence.
During a latched overvoltage, the PWM outputs will be
driven either low or three state, depending upon the VSEN
input. PWM outputs are driven low when the VSEN pin
detects that the CORE voltage is 15% above the
programmed VID level. This condition drives the PWM
outputs low, resulting in the lower or synchronous rectifier
MOSFETs to conduct and shunt the CORE voltage to
ground to protect the load.
If after this event, the CORE voltage falls below the
overvoltage limit (plus some hysteresis), the PWM outputs
will three state. The HIP6601B family drivers pass the three
state information along, and shuts off both upper and lower
MOSFETs. This prevents “dumping” of the output capacitors
back through the lower MOSFETs, avoiding a possibly
destructive ringing of the capacitors and output inductors. If
the conditions that caused the overvoltage still persist, the
PWM outputs will be cycled between three state and V
clamped to ground, as a hysteretic shunt regulator.
Undervoltage
The VSEN pin also detects when the CORE voltage falls
more than 10% below the VID programmed level. This
causes PGOOD to go low, but has no other effect on
operation and is not latched. There is also hysteresis in this
detection point.
10
CC
high to initiate a
CORE
HIP6301
HIP6301
Overcurrent
In the event of an overcurrent condition, the overcurrent
protection circuit reduces the average current delivered to
less than 25% of the current limit. When an overcurrent
condition is detected, the controller forces all PWM outputs
into a three state mode. This condition results in the gate
driver removing drive to the output stages. The HIP6301
goes into a wait delay timing cycle that is equal to the Soft-
Start ramp time. PGOOD also goes “low” during this time
due to VSEN going below its threshold voltage. To lower the
average output dissipation, the Soft-Start initial wait time is
increased from 32 to 2048 cycles, then the Soft-Start ramp is
initiated. At a PWM frequency of 200kHz, for instance, an
overcurrent detection would cause a dead time of 10.24ms,
then a ramp of 10.08ms.
At the end of the delay, PWM outputs are restarted and the
soft-start ramp is initiated. If a short is present at that time,
the cycle is repeated. This is the hiccup mode.
Figure 6 shows the supply shorted under operation and the
hiccup operating mode described above. Note that due to
the high short circuit current, overcurrent is detected before
completion of the start-up sequence so the delay is not quite
as long as the normal Soft-Start cycle.
FIGURE 6. SHORT APPLIED TO SUPPLY AFTER POWER-UP
SHORT APPLIED HERE
HICCUP MODE. SUPPLY POWERED BY ATX SUPPLY
ATX SUPPLY ACTIVATED BY ATX “PS-ON PIN”
CORE LOAD CURRENT = 31A, 5V LOAD = 5A
SUPPLY FREQUENCY = 200kHz, V
IN
December 27, 2004
= 12V
PGOOD
SHORT
CURRENT
50A/Div
FN4765.6