参数资料
| 型号： | ISL95870BHRZ-T |
| 厂商： | Intersil |
| 文件页数： | 19/28页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR PWM 1PHASE GPU 20QFN |
| 标准包装： | 6,000 |
| 应用： | 控制器，GPU 内核电源 |
| 输入电压： | 3.3 V ~ 25 V |
| 输出数： | 1 |
| 输出电压： | 0.5 V ~ 5 V |
| 工作温度： | -10°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-VFQFN 裸露焊盘 |
| 供应商设备封装： | 20-QFN（3x4） |
| 包装： | 带卷 (TR) |
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ISL95870, ISL95870A, ISL95870B
Stability
The removal of compensation derives from the R 4 modulator’s
lack of need for high DC gain. In traditional architectures, high DC
gain is achieved with an integrator in the voltage loop. The
integrator introduces a pole in the open-loop transfer function at
wide range of output filter choices. The result is a stable system
with no need for compensation components or complex
equations to properly tune the stability.
R2
low frequencies. That, combined with the double-pole from the
output L/C filter, creates a three pole system that must be
compensated to maintain stability.
V OUT
R1
V COMP
Classic control theory requires a single-pole transition through
unity gain to ensure a stable system. Current-mode architectures
(includes peak, peak-valley, current-mode hysteretic, R 3 and R 4 )
generate a zero at or near the L/C resonant point, effectively
canceling one of the system’s poles. The system still contains
two poles, one of which must be canceled with a zero before
unity gain crossover to achieve stability. Compensation
components are added to introduce the necessary zero.
V DAC
FIGURE 14. NON-INTEGRATED R4 ERROR-AMPLIFIER
CONFIGURATION
Figure 14 shows the R 4 error-amplifier that does not require an
integrator for high DC gain to achieve accurate regulation. The
result to the open loop response can be seen in Figure 15.
R4 LOOP GAIN (dB)
COMPENSATION TO COUNTER
INTEGRATOR
INTEGRATOR POLE
FOR HIGH DC GAIN
L/C DOUBLE-POLE
V OUT
V COMP
p1
p2
SYSTEM HAS 2 POLES
AND 1 ZERO
NO COMPENSATOR IS
V DAC
CURRENT-MODE
NEEDED
FIGURE 12. INTEGRATOR ERROR-AMPLIFIER CONFIGURATION
R3 LOOP GAIN (dB)
ZERO
z1
f (Hz)
p1
INTEGRATOR POLE
L/C DOUBLE-POLE
FIGURE 15. UNCOMPENSATED R4 OPEN-LOOP RESPONSE
Transient Response
p2
CURRENT-MODE
ZERO z1
p3
-20dB CROSSOVER
REQUIRED FOR STABILITY
COMPENSATOR TO
ADD z2 IS NEEDED
In addition to requiring a compensation zero, the integrator in
traditional architectures also slows system response to transient
conditions. The change in COMP voltage is slow in response to a
rapid change in output voltage. If the integrating capacitor is
removed, COMP moves as quickly as VOUT, and the modulator
immediately increases or decreases switching frequency to
recover the output voltage.
I OUT
f (Hz)
FIGURE 13. UNCOMPENSATED INTEGRATOR OPEN-LOOP RESPONSE
R4
R3
t
Figure 12 illustrates the classic integrator configuration for a
voltage loop error-amplifier. While the integrator provides the
high DC gain required for accurate regulation in traditional
technologies, it also introduces a low-frequency pole into the
control loop. Figure 13 shows the open-loop response that results
from the addition of an integrating capacitor in the voltage loop.
The compensation components found in Figure 12 are necessary
to achieve stability.
Because R 4 does not require a high-gain voltage loop, the
integrator can be removed, reducing the number of inherent
poles in the loop to two. The current-mode zero continues to
cancel one of the poles, ensuring a single-pole crossover for a
19
V COMP
t
V OUT
t
FIGURE 16. R3 vs R4 IDEALIZED TRANSIENT RESPONSE
FN6899.1
December 2, 2013
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL95870BHRZ-TS2490 | 制造商:Intersil Corporation 功能描述:IBM, ISL95870BHRZ-T W/CONTAINER LABELING - Tape and Reel |
| ISL95870BHRZ-TS2568 | 制造商:Intersil Corporation 功能描述:INTEL, ISL95870BHRTZ-T W/BARCODE LABELS, 12 MONTH D/C RESTRI - Tape and Reel |
| ISL95870BIRZ | 功能描述:电流型 PWM 控制器 0/2 BIT PWM GPU CONTLR FOR NOTEBOOK RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL95870BIRZ-T | 功能描述:电流型 PWM 控制器 0/2 BIT PWM GPU CONTLR FOR NOTEBOOK RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL95870HRUZ-T | 功能描述:电流型 PWM 控制器 0/2 BIT PWM GPU CONTLR FOR NOTEBOOK RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
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