- 您现在的位置：买卖IC网 > Sheet目录327 > HIP6021EVAL1 (Intersil)EVALUATION BOARD HIP6021
Application Note 9836
Over-Current Protection
The switching regulators within the HIP6020 and HIP6021
employ a lossless current sensing technique based on the
upper MOSFETs r DS(ON) . During the ON-time of the upper
MOSFET, its drain-to-source voltage is compared with a
user-adjustable voltage created by an internal current
source across R OCSET (i.e., R2, R3 in the HIP6020EVAL1
schematic). When the MOSFETs drain-to-source voltage
exceeds the preset threshold, the regulator immediately
shuts down all outputs and initiates a soft-start cycle. If the
condition persists, the third shutdown latches the chip off
and pulls the FAULT/RT pin high. Cycling the bias voltage
OFF and ON resets the protection circuitry.
The linear regulator outputs employ a different method of
overcurrent detection. Given the relatively large r DS(ON) of
the pass devices, a short-circuit condition usually translates
into a dip in the output voltage. If the output voltage (as
sensed at the feedback pin) dips below approximately 75%
of the set point, this undervoltage is interpreted as an
overcurrent event and the control IC reacts accordingly,
shutting down all outputs and cycling the soft-start.
blows due to the magnitude of the surge current being drawn
from the 5V input supply. Proper operation of this protection
feature is contingent, however, on the 12V bias voltage
being sufficiently high to turn on the lower MOSFET. The
circuit has been tested with several ATX supplies, and they
all produced acceptable bias voltage for the operation of the
protection circuitry and the on-board UltraFET MOSFETs.
Figure 6 depicts the same start-up scenario, this time with
the ATX supply control interface enabled. As seen in the
oscilloscope capture, as soon as power-on reset (POR)
thresholds are detected, the HIP6020/21 detects the
overvoltage condition and reports it on the FAULT/RT pin. In
turn, the control circuit shuts down the ATX supply by
generating a logic high at the PS-ON input, before any
expensive damage can occur.
10
FAULT/RT
0
10
+12VIN
0
2
The internal regulator is protected by an additional internal
output current mirror. Output current exceeding the preset
threshold (see data sheet) generates a similar response.
Any over-current event on any output is reported by the
toggle of the PGOOD output.
+5VIN
1
0
2
1
Over-Voltage Protection
The microprocessor core regulator (synchronous buck) has
VCC_CORE
0
0
20
40
60
80
100
120 140 160
a voltage-tracking over-voltage threshold set at 115%
(typically) of the DAC setting. In the case of an over-voltage
event, the microprocessor core regulator attempts to
regulate the output voltage at the over-voltage threshold. It
also reports the condition through a high output on the
FAULT/RT pin.
In addition to the normal over-voltage operation, the
microprocessor core regulator has another very useful
TIME (ms)
FIGURE 5. START-UP SEQUENCE WITH SHORTED Q1
(ATX CONTROL CIRCUIT BY-PASSED)
10
FAULT/RT
0
protection feature presented in Figures 5 and 6. In case of a
power-up sequence with a shorted upper MOSFET, the
microprocessor can be destroyed without the protective
circuitry integrated into the HIP6020/21. An independent
functional block acts upon the lower gate driver, regulating
the core voltage to around 1.3V until the controller bias
voltage reaches power-on threshold. At this point normal
operation resumes, core voltage is regulated to 115% of the
DAC setting (2.0V in this case), and fault condition is
reported on the FAULT/RT pin.
+12VIN
+5VIN
VCC_CORE
5
0
2
1
0
2
1
Figure 5 exemplifies operation of the evaluation board
without the help of the ATX supply control circuit (Figure 3).
Initially the core voltage is held around 1.3V until the power-
on threshold is reached (15ms till 50ms). Then the output
voltage is released to rise up to 115% of the DAC setting
(DAC = 2.0V). FAULT/RT goes high at this time signaling an
over-voltage condition. About 20ms later the 15A fuse (F1)
3
0
0 10 20 30 40 50 60 70 80
TIME (ms)
FIGURE 6. START-UP SEQUENCE WITH SHORTED Q1
(ATX CONTROL CIRCUIT ACTIVE)
UltraFET? is a trademark of Intersil Corporation.
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
HIP6301EVAL2
EVALUATION BOARD HIP6301
HIP6302EVAL1
EVALUATION BOARD HIP6302
HIP6521EVAL1
EVALUATION BOARD HIP6521
HIP6602BCR-T
IC DRVR MOSF 2CH SYC BUCK 16-QFN
HIP6603BCBZ
IC DRIVER MOSFET SYNC BUCK 8SOIC
HS0005KCU04H
EMULATOR E10A-USB SUPERH RISC
HT1010SAT3
SURGE SUPPRESS 15A 10OUT 10'C
HT10DBS
SURGE SUPPRESS 12A 10OUT 8'CORD
相关代理商/技术参数
HIP6028
制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Advanced PWM and Dual Linear Power Control with Integrated ACPI Support Interface
HIP6028CB
制造商:Rochester Electronics LLC 功能描述:- Bulk
HIP6028CB WAF
制造商:Harris Corporation 功能描述:
HIP6028EVAL1
制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Advanced PWM and Dual Linear Power Control with Integrated ACPI Support Interface
HIP6034CB
制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog IC
HIP6034CB-T
制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog IC
HIP6200
制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Transient Voltage Regulator DeCAPitator⑩
HIP6200CB
制造商:Rochester Electronics LLC 功能描述:- Bulk