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参数资料
| 型号： | ISL6522CB |
| 厂商： | Intersil |
| 文件页数： | 9/15页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BST PWM VM 14-SOIC |
| 标准包装： | 50 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1MHz |
| 占空比： | 100% |
| 电源电压： | 10.8 V ~ 13.2 V |
| 降压： | 是 |
| 升压： | 是 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | 0°C ~ 70°C |
| 封装/外壳： | 14-SOIC（0.154"，3.90mm 宽） |
| 包装： | 管件 |
ISL6522
OSC
DRIVER
V IN
4. Place 1 ST Pole at the ESR Zero
5. Place 2 ND Pole at Half the Switching Frequency
-
? V OSC
PWM
COMPARATOR
+
DRIVER
L O
PHASE
C O
V OUT
6. Check Gain against Error Amplifier ’s Open-Loop Gain
7. Estimate Phase Margin - Repeat if Necessary
Figure 8 shows an asymptotic plot of the DC-DC converter’s
-
Z FB
V E/A
+
ERROR
AMP
Z IN
REFERENCE
ESR
(PARASITIC)
gain vs. frequency. The actual modulator gain has a high gain
peak due to the high Q factor of the output filter and is not
shown in Figure 8. Using the above guidelines should give a
compensation gain similar to the curve plotted. The open loop
error amplifier gain bounds the compensation gain. Check the
compensation gain at F P2 with the capabilities of the error
amplifier. The closed loop gain is constructed on the log-log
graph of Figure 8 by adding the modulator gain (in dB) to the
DETAILED COMPENSATION COMPONENTS
compensation gain (in dB). This is equivalent to multiplying
the modulator transfer function to the compensation transfer
C2
Z FB
Z IN
V OUT
function and plotting the gain.
C1
COMP
-
+
R2
FB
C3
R3
R1
100
80
60
40
20LOG
F Z1 F Z2
F P1
F P2
OPEN LOOP
ERROR AMP GAIN
ISL6522
REF
20
0
(R2/R1)
20LOG
(V IN / ? V OSC )
COMPENSATION
-20
MODULATOR
GAIN
FIGURE 7. VOLTAGE - MODE BUCK CONVERTER
COMPENSATION DESIGN
Modulator Break Frequency Equations
-40
-60
10
100
GAIN
1K
F LC
10K
F ESR
100K
1M
CLOSED LOOP
GAIN
10M
F LC = ---------------------------------------
F ESR = ---------------------------------------------
1
2 π ? L O ? C O
1
2 π ? ( ESR ? C O )
FREQUENCY (Hz)
FIGURE 8. ASYMPTOTIC BODE PLOT OF CONVERTER GAIN
The compensation network consists of the error amplifier
(internal to the ISL6522) and the impedance networks Z IN
and Z FB . The goal of the compensation network is to provide
a closed loop transfer function with the highest 0dB crossing
frequency (f 0dB ) and adequate phase margin. Phase margin
is the difference between the closed loop phase at f 0dB and
180 degrees . The equations below relate the compensation
network’s poles, zeros and gain to the components (R1, R2,
R3, C1, C2, and C3) in Figure 8. Use these guidelines for
locating the poles and zeros of the compensation network:
Compensation Break Frequency Equations
The compensation gain uses external impedance networks
Z FB and Z IN to provide a stable, high bandwidth (BW) overall
loop. A stable control loop has a gain crossing with
-20dB/decade slope and a phase margin greater than 45
degrees. Include worst case component variations when
determining phase margin.
Component Selection Guidelines
Output Capacitor Selection
An output capacitor is required to filter the output and supply
the load transient current. The filtering requirements are a
function of the switching frequency and the ripple current.
F Z1 = ----------------------------------
F Z2 = ------------------------------------------------------
F P1 = -------------------------------------------------------
2 π ? R2 ? ? ---------------------- ?
F P2 = ----------------------------------
1
2 π ? R 2 ? C1
1
2 π ? ( R1 + R3 ) ? C3
1
C1 ? C2
? C1 + C2 ?
1
2 π ? R3 ? C3
The load transient requirements are a function of the slew
rate (di/dt) and the magnitude of the transient load current.
These requirements are generally met with a mix of
capacitors and careful layout.
Modern microprocessors produce transient load rates above
1. Pick Gain (R2/R1) for desired converter bandwidth
2. Place 1 ST Zero Below Filter ’s Double Pole
(~75% F LC )
3. Place 2 ND Zero at Filter ’s Double Pole
9
1A/ns. High frequency capacitors initially supply the transient
and slow the current load rate seen by the bulk capacitors.
The bulk filter capacitor values are generally determined by
FN9030.8
March 10, 2006
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6522CBR5190 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Intersil Corporation 功能描述: |
| ISL6522CB-T | 功能描述:IC REG CTRLR BST PWM VM 14-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
| ISL6522CB-TR5190 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Intersil Corporation 功能描述: |
| ISL6522CBZ | 功能描述:电压模式 PWM 控制器 PWM CNTRLR DDRG 14LD N 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 |
| ISL6522CBZA | 功能描述:IC REG CTRLR BST PWM VM 14-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
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