参数资料
| 型号： | ISL6526IR-T |
| 厂商： | Intersil |
| 文件页数： | 8/15页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 16-QFN |
| 标准包装： | 6,000 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 340kHz |
| 占空比： | 100% |
| 电源电压： | 2.97 V ~ 3.63 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 16-VQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
ISL6526, ISL6526A
+3.3V
V OUT (2.5V)
VCC
CPVOUT
BOOT
D1
VIN
ISL6526,
ISL6526A
UGATE
PHASE
C4
Q1
L OUT
V OUT
0V
LGATE
Q2
+
INTERNAL SOFT-START FUNCTION
C OUT
FB
COMP
C1
R1
C3
R3
DELAY INTERVAL
C2
R2
R4
t0
t1
t2
TIME
FIGURE 3. OVERCURRENT PROTECTION RESPONSE
FIGURE 2. OUTPUT VOLTAGE SELECTION
The overcurrent function will trip at a peak inductor current
Overcurrent Protection
(I PEAK) determined by Equation 3:
I PEAK = -----------------------------------------------------
The overcurrent function protects the converter from a shorted
output by using the upper MOSFET ON-resistance, r DS(ON) ,
to monitor the current. This method enhances the converter’s
I OCSET x R OCSET
r DS ( ON )
(EQ. 3)
3. Determine I PEAK for I PEAK > I OUT ( MAX ) + ---------- ,
efficiency and reduces cost by eliminating a current sensing
resistor.
The overcurrent function cycles the soft-start function in a
hiccup mode to provide fault protection. A resistor (R OCSET )
page 3). An internal 20μA (typical) current sink develops a
voltage across R OCSET that is referenced to V IN . When the
voltage across the upper MOSFET (also referenced to V IN )
exceeds the voltage across R OCSET , the overcurrent function
initiates a soft-start sequence.
Figure 3 illustrates the protection feature responding to an
overcurrent event. At time t0, an overcurrent condition is
sensed across the upper MOSFET. As a result, the regulator
is quickly shutdown and the internal soft-start function begins
producing soft-start ramps. The delay interval seen by the
output is equivalent to three soft-start cycles. The fourth
internal soft-start cycle initiates a normal soft-start ramp of the
output, at time t1. The output is brought back into regulation
by time t2, as long as the overcurrent event has cleared.
Had the cause of the overcurrent still been present after the
delay interval, the overcurrent condition would be sensed and
the regulator would be shut down again for another delay
interval of three soft-start cycles. The resulting hiccup mode
style of protection would continue to repeat indefinitely.
8
where I OCSET is the internal OCSET current source (20μA
typical). The OC trip point varies mainly due to the MOSFET
r DS(ON) variations. To avoid overcurrent tripping in the
normal operating load range, find the R OCSET resistor from
Equation 3 with:
1. The maximum r DS(ON) at the highest junction
temperature.
2. The minimum I OCSET from the specification table.
( Δ I )
2
where Δ I is the output inductor ripple current.
A small ceramic capacitor should be placed in parallel with
R OCSET to smooth the voltage across R OCSET in the
presence of switching noise on the input voltage.
Current Sinking
The ISL6526, ISL6526A incorporate a MOSFET shoot-through
protection method which allows a converter to sink current as
well as source current. Care should be exercised when
designing a converter with the ISL6526, ISL6526A when it is
known that the converter may sink current.
When the converter is sinking current, it is behaving as a
boost converter that is regulating its input voltage. This
means that the converter is boosting current into the input
rail of the regulator. If there is nowhere for this current to go,
FN9055.10
November 24, 2008
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6526IR-TR51 | 制造商:Intersil Corporation 功能描述: |
| ISL6526IR-TR5146 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| ISL6526IR-TR5164 | 制造商:Intersil Corporation 功能描述: |
| ISL6526IRZ | 功能描述:电压模式 PWM 控制器 300 KHZ SINGLE PWM W/CHRG PUMP 16LD RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| ISL6526IRZ-T | 功能描述:电压模式 PWM 控制器 300 KHZ SINGLE PWM W/CHRG PUMP 16LD RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
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