- 您现在的位置：买卖IC网 > PDF目录5139 > MAX1585ETJ+ (Maxim Integrated Products)IC DGTL CAM PWR SUP 5CH 32TQFN PDF资料下载
参数资料
| 型号： | MAX1585ETJ+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 24/29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： | 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： | 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 |
| 产品目录页面： | 1422 (CN2011-ZH PDF) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页当前第24页第25页第26页第27页第28页第29页
5-Channel Slim DSC Power Supplies
MAX1585 AUX2 Inverter Compensation,
Discontinuous Inductor Current
If the load current is very low (40mA or less), discontin-
uous current is preferred for simple loop compensation
and freedom from duty-cycle restrictions on the inverter
input-output ratio. To ensure discontinuous operation,
the inductor must have a sufficiently low inductance to
fully discharge on each cycle. This occurs when:
L < [V IN / (|V OUT | + V IN )] 2 R LOAD / (2f OSC )
A discontinuous current inverter has a single pole at:
f P = 2 / (2 π x R LOAD x C OUT )
Choose the integrator cap so the unity-gain crossover,
f C , occurs at f OSC / 10 or lower. Note that for many AUX
circuits 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 the following:
C C = [V IN / (K 1/2 x V RAMP ][V REF / (V OUT + V REF )] [g M /
(2 π x f C )]
where:
K = 2L x f OSC / R LOAD, and V RAMP is the internal volt-
age ramp of 1.25V.
The C C R C zero then is used to cancel the f P pole, so:
R C = (R LOAD x C OUT ) / (2 C C )
MAX1585 AUX2 Inverter Compensation,
Continuous Inductor Current
Continuous inductor current may be more suitable for
larger load currents (50mA or more). It improves effi-
ciency by lowering the ratio between peak inductor cur-
rent and output current. It does this at the expense of a
larger inductance value that requires larger size for a
given current rating. With continuous inductor-current
inverter operation, there is a right-half-plane zero,
Z RHP , at:
Z RHP = [(1 - D) 2 / D] x R LOAD / (2 π x L)
where D = |V OUT | / (|V OUT | + V IN ) (in an inverter).
There is a complex pole pair at:
f 0 = (1 - D) / (2 π (L x C) 1/2 )
If the zero due to the output-capacitor capacitance and
ESR is less than 1/10 the right-half-plane zero:
Z COUT = 1 / (2 π x C OUT x R ESR ) < Z RHP / 10
Then choose C C so 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 REF / (V REF + |V OUT |)][g M / (2 π x
Z COUT )]
Choose R C to place the integrator zero, 1 / (2 π x R C x
C C ), at f 0 to cancel one of the pole pairs:
R C = (L x C OUT ) 1/2 / [(1 - D) x C C ]
If Z COUT is not less than Z RHP / 10 (as is typical with
ceramic output capacitors) and continuous conduction
is required, then cross the loop over before Z RHP and f 0 :
f C < f 0 / 10, and f C < Z RHP / 10
In that case:
C C = (V IN / V RAMP )[V REF / (V REF + |V OUT |)][g M / (2 π x f C )]
Place:
1 / (2 π x R C x C C ) = 1 / (2 π x R LOAD x C OUT ), so that
R C = R LOAD x C OUT / C C
Or, reduce the inductor value for discontinuous operation.
Applications Information
LED, LCD, and Other Boost Applications
Any AUX 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, generat-
ing 15V or a similar voltage for LCD bias, or generating
a step-up current source to efficiently drive a series
array of white LEDs to display backlighting. Figures 5
and 6 show examples of these applications.
Multiple-Output Flyback Circuits
Some applications require multiple voltages from a sin-
gle converter channel. This is often the case when gen-
erating voltages for CCD bias or LCD power. Figure 7
shows a two-output flyback configuration with AUX_.
The controller drives an external MOSFET that switches
the transformer primary. Two transformer secondaries
generate the output voltages. Only one positive output
voltage can be fed back, so the other voltages are set
by the turns ratio of the transformer secondaries. The
load stability of the other secondary voltages depends
on transformer leakage, inductance, and winding resis-
tance. Voltage regulation is best when the load on the
secondary that is not fed back is small compared to the
load on the one that is fed back. Regulation also
improves if the load current range is limited. Consult
the transformer manufacturer for the proper design for
a given application.
24
______________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| HBM44DRAS | CONN EDGECARD 88POS R/A .156 SLD |
| ESM44DSXN | CONN EDGECARD 88POS DIP .156 SLD |
| MAX1778EUG+T | IC DCDC CONV MULTI OUT 24TSSOP |
| RYM25DRSN-S288 | CONN EDGECARD 50POS .156 EXTEND |
| SIP21106DR-46-E3 | IC REG LDO 4.6V .15A SC70-5 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1585ETJ+ | 功能描述:直流/直流开关转换器 5Ch Slim DSC Power Supply RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX1585ETJ+T | 功能描述:直流/直流开关转换器 5Ch Slim DSC Power Supply RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX1585ETJ-T | 功能描述:直流/直流开关转换器 5Ch Slim DSC Power Supply RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX1585EVKIT | 功能描述:直流/直流开关转换器 Evaluation Kit for the MAX1585 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| MAX1586AETM | 功能描述:直流/直流开关调节器 PMICs w/Dynamic Core for PDAs RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
发布紧急采购，3分钟左右您将得到回复。