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参数资料
| 型号： | MAX1565ETJ+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 21/26页 |
| 文件大小： | 0K |
| 描述： | IC DGTL CAM PWR-SUP 5CH 32TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 应用： | 转换器控制器，数字式相机 |
| 输入电压： | 0.7 V ~ 5.5 V |
| 输出数： | 5 |
| 输出电压： | 3.3V，1.25 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
| 包装： | 管件 |
Small, High-Efficiency, Five-Channel
Digital Still Camera Power Supply
Discontinuous Inductor Current
When the inductor current falls to zero on each switching
cycle, it is described as discontinuous. The inductor is
not utilized as efficiently as with continuous current. This
often has little negative impact in light-load applications
since the coil losses may already be low compared to
other losses. A benefit of discontinuous inductor cur-
rent is more flexible loop compensation and no maxi-
mum duty-cycle restriction on boost ratio.
To ensure discontinuous operation, the inductor must
have a sufficiently low inductance to fully discharge on
Choose C C such that the crossover frequency f C
occurs at Z COUT . The ESR zero provides a phase boost
at crossover.
C C = (V IN /V RAMP )(V FB /V OUT )(g M /(2 π Z COUT ))
Choose R C to place the integrator zero, 1/(2 π R C C C ), at
f 0 to cancel one of the pole pairs:
R C = V IN (L C OUT ) 1/2 /(V OUT C C )
If Z COUT is not less than f RHPZ /10 (as is typical with
ceramic output capacitors) and continuous conduction is
required, then cross the loop over before f RHPZ and f 0 :
each cycle. This occurs when:
L < [V IN 2 (V OUT - V IN )/V OUT3 ] [R LOAD /(2 f OSC )]
In that case:
f C < f 0 /10, and f C < f RHPZ /10
A discontinuous current boost has a single pole at:
f P = (2V OUT - V IN )/(2 π R LOAD C OUT V OUT )
Choose the integrator capacitor such that the unity-gain
crossover (f C ) occurs at f OSC /10 or lower. Note that for
many auxiliary circuits, such as those powering motors,
LEDs, or other loads that do not require fast transient
response, it is often acceptable to overcompensate by
setting f C at f OSC /20 or lower. C C is then determined by:
C C = [2V OUT V IN /((2V OUT - V IN )V RAMP )]
[V OUT /(K(V OUT - V IN ))] 1/2 [(V FB /V OUT )
(g M /(2 π f C ))]
where K = 2 L f OSC /R LOAD, and V RAMP is the internal
slope compensation voltage ramp of 1.25V. The C C R C
zero is then used to cancel the f P pole, so:
R C = R LOAD C OUT V OUT /[(2V OUT - V IN ) C C ]
Continuous Inductor Current
Continuous inductor current can sometimes improve
boost efficiency by lowering the ratio between peak
inductor current and output current. It does this at the
C C = (V IN /V RAMP )(V FB /V OUT )(g M /(2 π f C ))
Place 1/(2 π R C C C ) = 1/(2 π R LOAD C OUT ), so that R C =
R LOAD C OUT /C C or reduce the inductor value for dis-
continuous operation.
Applications Information
LED, LCD, and Other Boost Applications
Any auxiliary channel can be used for a wide variety of
step-up applications. These include generating 5V or
some other voltage for motor or actuator drive, generating
15V or a similar voltage for LCD bias, or generating a
step-up current source to efficiently drive a series array
of white LEDs for display backlighting. Figures 5 and 6
show examples of these applications.
TO V BATT
4.7 μ F
4.7 μ H
expense of a larger inductance value that requires larger
size for a given current rating. With continuous inductor
current boost operation, there is a right-plane zero at:
f RHPZ = (1 - D) 2 R LOAD /(2 π L)
15V
100mA
22 μ F
1.1M ?
DL_
OUTSU
where (1 - D) = V IN /V OUT (in a boost converter). A com-
plex pole pair is located at:
f 0 = V OUT /[2 π V IN (L C OUT ) 1/2 ]
If the zero due to the output capacitor capacitance and
ESR is less than 1/10 the right-plane zero:
100k ?
FB_
AUX_
PWM
MAX1565
(PARTIAL)
Z COUT = 1/(2 π C OUT R ESR ) < f RHPZ /10
Figure 5. Using an AUX_ Controller Channel to Generate LCD
Bias
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21
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1565ETJ+ | 功能描述:PMIC 解决方案 5Ch Digital Camera Power Supply RoHS:否 制造商:Texas Instruments 安装风格:SMD/SMT 封装 / 箱体:QFN-24 封装:Reel |
| MAX1565ETJ+T | 功能描述:PMIC 解决方案 5Ch Digital Camera Power Supply RoHS:否 制造商:Texas Instruments 安装风格:SMD/SMT 封装 / 箱体:QFN-24 封装:Reel |
| MAX1565ETJ-T | 功能描述:PMIC 解决方案 5Ch Digital Camera Power Supply RoHS:否 制造商:Texas Instruments 安装风格:SMD/SMT 封装 / 箱体:QFN-24 封装:Reel |
| MAX1565EVKIT | 制造商:Maxim Integrated Products 功能描述:SMALL, HIGH-EFFICIENCY, FIVE-CHANNEL DSC - Bulk |
| MAX1566ETL | 功能描述:PMIC 解决方案 RoHS:否 制造商:Texas Instruments 安装风格:SMD/SMT 封装 / 箱体:QFN-24 封装:Reel |
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