参数资料
| 型号： | ISL62881CIRTZ |
| 厂商： | Intersil |
| 文件页数： | 13/37页 |
| 文件大小： | 0K |
| 描述： | IC REG PWM SGL PHASE 28TQFN |
| 标准包装： | 75 |
| 应用： | 控制器，Intel IMVP-6.5? |
| 输入电压： | 4.5 V ~ 25 V |
| 输出数： | 1 |
| 输出电压： | 0.013 V ~ 1.5 V |
| 工作温度： | -40°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（4x4） |
| 包装： | 管件 |
| 配用： | ISL62881CCPUEVAL2Z-ND - EVAL BOARD ISL62881CCPU 28QFN |
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ISL62881C, ISL62881D
Diode Emulation and Period Stretching
VDD
VR_ON
5mV/μs
PHASE
UGATE
DAC
2.5mV/μs
90% VBOOT
800μs
VID
COMMAND
VOLTAGE
13 SWITCHING CYCLES
LGATE
CLK_EN#
IL
PGOOD
~7ms
FIGURE 10. SOFT-START WAVEFORMS FOR CPU VR
FIGURE 8. DIODE EMULATION
ISL62881C can operate in diode emulation (DE) mode to
improve light load efficiency. In DE mode, the low-side
MOSFET conducts when the current is flowing from
source to drain and doesn’t not allow reverse current,
VDD
APPLICATION
emulating a diode. As shown in Figure 8, when LGATE is
on, the low-side MOSFET carries current, creating
negative voltage on the phase node due to the voltage
drop across the ON-resistance. The ISL62881C monitors
VR_ON
5mV/μs
90%
120μs
VID COMMAND VOLTAGE
the current through monitoring the phase node voltage.
It turns off LGATE when the phase node voltage reaches
zero to prevent the inductor current from reversing the
DAC
13 SWITCHING CYCLES
direction and creating unnecessary power loss.
If the load current is light enough, as Figure 9 shows, the
inductor current will reach and stay at zero before the
next phase node pulse, and the regulator is in
discontinuous conduction mode (DCM). If the load
current is heavy enough, the inductor current will never
reach 0A, and the regulator is in CCM although the
controller is in DE mode.
CCM/DCM BOUNDARY
VW
VCRS
CLK_EN#
~7ms
PGOOD
FIGURE 11. SOFT-START WAVEFORMS FOR GPU VR
APPLICATION
Figure 9 shows the operation principle in diode emulation
mode at light load. The load gets incrementally lighter in
the three cases from top to bottom. The PWM on-time is
determined by the VW window size, therefore is the
same, making the inductor current triangle the same in
the three cases. The ISL62881C clamps the ripple
capacitor voltage V crs in DE mode to make it mimic the
inductor current. It takes the COMP voltage longer to hit
IL
VCRS
VW
LIGHT DCM
V crs , naturally stretching the switching period. The
inductor current triangles move further apart from each
other such that the inductor current average value is
equal to the load current. The reduced switching
frequency helps increase light load efficiency.
Start-up Timing
IL
VCRS
VW
DEEP DCM
With the controller's V DD voltage above the POR
threshold, the start-up sequence begins when VR_ON
exceeds the 3.3V logic high threshold.
Figure 10 shows the typical start-up timing when the
ISL62881C is configured for CPU VR application. The
ISL62881C uses digital soft-start to ramp up DAC to the
boot voltage of 1.1V at about 2.5mV/μs. Once the output
IL
FIGURE 9. PERIOD STRETCHING
13
voltage is within 10% of the boot voltage for 13 PWM
cycles (43μs for frequency = 300kHz), CLK_EN# is
pulled low and DAC slews at 5mV/μs to the voltage set
by the VID pins. PGOOD is asserted high in
approximately 7ms. Similar results occur if VR_ON is tied
FN7596.0
March 8, 2010
相关PDF资料 |
PDF描述 |
|---|---|
| ISL62881HRTZ | IC REG PWM SGL PHASE 28TQFN |
| ISL62882IRTZ | IC REG PWM 2PHASE BUCK 40TQFN |
| ISL62883IRTZ | IC REG PWM 3PHASE BUCK 40TQFN |
| ISL6292BCRZ | IC CHARGER LI-ION 4.2V 4X4 16QFN |
| ISL6294IBZ | IC CHRGR LI-ION SGL 8-SOIC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL62881CIRTZ-T | 功能描述:直流/直流开关调节器 1-PHS PWM BUCKG FOR MICROPROC PWR SUPPLY RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| ISL62881D | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Single-Phase PWM Regulator for IMVP-6.5a?￠ Mobile CPUs and GPUs |
| ISL62881DHRTZ | 功能描述:直流/直流开关调节器 1 PHS CNTRLR W/INTEG DRVR 32LD 5X5 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| ISL62881DHRTZ-T | 功能描述:直流/直流开关调节器 1 PHS CNTRLR W/INTEG DRVR 32LD 5X5 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| ISL62881HRTZ | 功能描述:直流/直流开关调节器 1 PHS PWM BUCKG FOR MICROPROCESR PWR SUP RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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