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参数资料
| 型号： | ISL6439IRZ-T |
| 厂商： | Intersil |
| 文件页数： | 10/15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： | 3.3 V ~ 5 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) |
ISL6439, ISL6439A
the modulator is simply the input voltage (V IN ) divided by the
peak-to-peak oscillator voltage Δ V OSC .
Compensation Break Frequency Equations
F Z1 = ----------------------------------
F P1 = ---------------------------------------------------------
2 π x R 2 x ? ---------------------- ?
OSC
PWM
COMPARATOR
DRIVER
V IN
L O
V OUT
1
2 π × R 2 × C 2
1
? C 1 x C 2 ?
? C 1 + C 2 ?
F Z2 = -------------------------------------------------------
F P2 = ------------------------------------
Δ V OSC
-
+
DRIVER
PHASE
C O
ESR
1
2 π x ( R 1 + R 3 ) x C 3
1
2 π x R 3 x C 3
Z FB
V E/A
-
+
ERROR
AMP
Z IN
REFERENCE
(PARASITIC)
(EQ. 5)
Figure 6 shows an asymptotic plot of the DC/DC converter’s
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 6. Using the above guidelines should give a
DETAILED COMPENSATION COMPONENTS
Compensation Gain similar to the curve plotted. The open
C 2
C 1
R 2
Z FB
C 3
Z IN
R 3
V OUT
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 graph of Figure 6 by adding the Modulator Gain (in dB) to
COMP
-
+
FB
R 1
the Compensation Gain (in dB). This is equivalent to
multiplying the modulator transfer function to the
compensation transfer function and plotting the gain.
The compensation gain uses external impedance networks
ISL6439
REFERENCE
Z FB and Z IN to provide a stable, high bandwidth (BW) overall
loop. A stable control loop has a gain crossing with
FIGURE 5. VOLTAGE-MODE BUCK CONVERTER
COMPENSATION DESIGN
-20dB/decade slope and a phase margin greater than 45
degrees. Include worst case component variations when
determining phase margin.
Modulator Break Frequency Equations
F LC = ------------------------------------------
F ESR = -------------------------------------------
? V IN ?
1
2 π x L O x C O
1
2 π x ESR x C O
(EQ. 4)
100
80
60
F Z1
F Z2
F P1
F P2
OPEN LOOP
ERROR AMP GAIN
20 log ? ---------------- ?
? V OSC ?
The compensation network consists of the error amplifier
(internal to the ISL6439) and the impedance networks Z IN
and Z FB . The goal of the compensation network is to provide
40
20
COMPENSATION
GAIN
20 log ? -------- ?
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 expressions in Equation 5 relate the
compensation network’s poles, zeros and gain to the
0
-20
-40
R2
? R1 ?
MODULATOR
GAIN
F LC
F ESR
LOOP GAIN
components (R 1 , R 2 , R 3 , C 1 , C 2 , and C 3 ) in Figure 5. Use
-60
10
100
1K
10K
100K
1M
10M
these guidelines for locating the poles and zeros of the
compensation network:
1. Pick gain (R 2 /R 1 ) for desired converter bandwidth.
2. Place first zero below filter’s double pole (~75% F LC ).
3. Place second zero at filter ’s double pole.
4. Place first pole at the ESR zero.
5. Place second pole at half the switching frequency.
6. Check gain against error amplifier ’s open-loop gain.
7. Estimate phase margin - repeat if necessary.
10
FREQUENCY (Hz)
FIGURE 6. ASYMPTOTIC BODE PLOT OF CONVERTER GAIN
Component Selection Guidelines
Charge Pump Capacitor Selection
A capacitor across pins CT1 and CT2 is required to create
the proper bias voltage for the ISL6439 when operating the
IC from 3.3V. Selecting the proper capacitance value is
important so that the bias current draw and the current
required by the MOSFET gates do not overburden the
FN9057.5
November 5, 2008
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| ISL6440EVAL1Z | 功能描述:EVALUATION BOARD FOR ISL6440 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ISL6440IA | 功能描述:IC REG CTRLR BUCK PWM CM 24-QSOP 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) |
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