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参数资料
| 型号： | ADP1821ARQZ-R7 |
| 厂商： | Analog Devices Inc |
| 文件页数： | 16/24页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 16-QSOP |
| 标准包装： | 1 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 720kHz |
| 占空比： | 90% |
| 电源电压： | 3.7 V ~ 5.5 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-SSOP（0.154"，3.90mm 宽） |
| 包装： | 标准包装 |
| 产品目录页面： | 791 (CN2011-ZH PDF) |
| 其它名称： | ADP1821ARQZ-R7DKR |
ADP1821
2 π R Z
Two common compensation schemes are used, which are
sometimes referred to as Type II or Type III compensation,
depending on whether the compensation design includes two
or three poles. (Dominant pole compensations, or single pole
compensation, is referred to as Type I compensation, but it is
not very useful for dealing successfully with switching regulators.)
f P 1 =
f P 2 =
1
C I C HF
C I + C HF
1
2 π R FF C FF
(29)
(30)
If the zero produced by the ESR of the output capacitor provides
sufficient phase boost at crossover, Type II compensation is
adequate. If the phase boost produced by the ESR of the output
capacitor is not sufficient, another zero is added to the compen-
sation network, and thus Type III is used.
In Figure 17, the location of the ESR zero corner frequency gives
where:
f Z1 is the zero produced in the Type II compensation.
f Z2 is the zero produced in the Type III compensation.
f P1 is the pole produced in the Type II compensation.
f P2 in the pole produced in the Type III compensation.
Type II Compensator
f LC f ESR1 f ESR2 f ESR3 f CO f SW
significantly different net phase at the crossover frequency.
LC FILTER BODE PLOT
PHASE CONTRIBUTION AT CROSSOVER
OF VARIOUS ESR ZERO CORNERS
GAIN
0dB
G
(dB)
PHASE
–1
S
LO
PE
f Z
f P
–1
S
LO
PE
–40dB/dec
FREQUENCY
–180°
–270°
C HF
–20dB/dec
R Z
C I
FROM
V OUT
R TOP
R BOT
EA
COMP
TO PWM
VREF
0V
VRAMP
PHASE
0°
Figure 18. Type II Compensation
If the output capacitor ESR zero frequency is sufficiently low (≤ ?
of the crossover frequency), use the ESR to stabilize the regulator.
–90°
Φ 1
In this case, use the circuit shown in Figure 18. Calculate the
compensation resistor, Rz, with the following equation:
V IN LC
f
–180°
Φ 2
Φ 3
R Z =
where:
R TOP V RAMP f ESR f CO
2
(31)
Figure 17. LC Filter Bode Plot
Use the following guidelines for selecting between Type II and
Type III compensators.
f CO is chosen to be 1/10 of f SW .
V RAMP is 1.25 V.
Next, choose the compensation capacitor to set the compensation
zero, f Z1 , to the lesser of ? of the crossover frequency or ? of the
If f ESRZ ≤
f CO
> CO , use Type III compensation.
If f ESRZ
f Z 1 =
= =
, use Type II compensation.
2
f
2
The following equations were used for the calculation of the
LC resonant frequency
f CO f SW
4 40
or
1
2 π R Z C I
(32)
f Z 1 =
(27)
f Z 1 =
=
1
2 π R Z C I
f LC 1
2 2 π R Z C I
Solving for C I in Equation 32 yields
(33)
f Z 2 =
1
2 π C FF ( R TOP + R FF )
(28)
C I =
20
π R Z f SW
(34)
Rev. C | Page 16 of 24
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP1821-BL1-EVZ | 制造商:Analog Devices 功能描述:Evaluation Board For Step-Down DC-To-DC Controller 制造商:Analog Devices 功能描述:BLANK ADISIMPOWER EVAL ADP1821 - Boxed Product (Development Kits) |
| ADP1821-BL2-EVZ | 制造商:Analog Devices 功能描述:Evaluation Board For Step-Down DC-To-DC Controller 制造商:Analog Devices 功能描述:BLANK ADISIMPOWER EVAL ADP1821 - Boxed Product (Development Kits) |
| ADP1821-EVAL | 功能描述:电源管理IC开发工具 Evaluation Board I.C. RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| ADP1822 | 制造商:AD 制造商全称:Analog Devices 功能描述:PWM, Step-Down DC-to-DC Controller with Margining and Tracking |
| ADP1822ARQZ-R7 | 功能描述:IC REG CTRLR BUCK PWM VM 24-QSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:75 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.3 V ~ 13.5 V 降压:是 升压:是 回扫:是 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:8-SOIC（0.154"，3.90mm 宽） 包装:管件 产品目录页面:1051 (CN2011-ZH PDF) 其它名称:296-2543-5 |
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