- 您现在的位置：买卖IC网 > PDF目录1840 > MAX17528GTJ+T (Maxim Integrated Products)IC CTLR PWM VID PS 1PH 32-TQFN PDF资料下载
参数资料
| 型号： | MAX17528GTJ+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 31/41页 |
| 文件大小： | 0K |
| 描述： | IC CTLR PWM VID PS 1PH 32-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 系列： | Quick-PWM™ |
| 应用： | 控制器，Intel IMVP-6.5? GMCH |
| 输入电压： | 4.5 V ~ 5.5 V |
| 输出数： | 1 |
| 输出电压： | 0.01 V ~ 1.5 V |
| 工作温度： | -40°C ~ 105°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： | 带卷 (TR) |
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页第24页第25页第26页第27页第28页第29页第30页当前第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页
1-Phase Quick-PWM
Intel IMVP-6.5/GMCH Controllers
I LOAD ( SKIP ) = ? SW OUT ? ? IN OUT ?
t TRAN ( START ) =
Automatic Pulse-Skipping Switchover
In skip mode (SKIP = high), an inherent automatic
switchover to PFM takes place at light loads (Figure 8).
This switchover is affected by a comparator that truncates
the low-side switch on-time at the inductor current’s zero
crossing. The zero-crossing comparator senses the
inductor current across the low-side MOSFETs. Once
V LX drops below the zero-crossing comparator threshold
(see the Electrical Characteristics table), the comparator
forces DL low (Figure 3). This mechanism causes the
threshold between pulse-skipping PFM and nonskipping
PWM operation to coincide with the boundary between
continuous and discontinuous inductor-current opera-
tion. The PFM/PWM crossover occurs when the load-cur-
rent is equal to 1/2 the peak-to-peak ripple current,
which is a function of the inductor value (Figure 8). For a
battery input range of 7V to 20V, this threshold is relative-
ly constant, with only a minor dependence on the input
voltage due to the typically low duty cycles. The total
load current at the PFM/PWM crossover threshold
(I LOAD(SKIP) ) is approximately:
? t V ? ? V ? V ?
? L ? ? V IN ?
The switching waveforms might appear noisy and asyn-
chronous when light loading activates pulse-skipping
operation, but this is a normal operating condition that
results in high light-load efficiency. Trade-offs between
PFM noise and light-load efficiency are made by
varying the inductor value. Generally, low inductor val-
ues produce a broader efficiency vs. load curve, while
higher values result in higher full-load efficiency
(assuming that the coil resistance remains fixed) and
less output voltage ripple. Penalties for using higher
inductor values include larger physical size and
degraded load-transient response, especially at low
input-voltage levels.
Power-Up Sequence (POR, UVLO)
The MAX17528 is enabled when SHDN is driven high
(Figures 9 and 10). The internal reference powers up
first, followed by the analog control circuitry. Roughly
50μs after the analog control circuitry powers up, the
PWM controller is enabled and begins the soft-start
sequence.
Power-on reset (POR) occurs when V CC rises above
approximately 2V, resetting the fault latch and prepar-
ing the controller for operation. The V CC UVLO circuitry
inhibits switching until V CC rises above 4.25V. The con-
troller powers up the reference once the system
enables the controller, V CC is above 4.25V, and SHDN
is driven high. The soft-start sequence ramps the out-
put voltage up to the target voltage—either the 1.1V
boot voltage for IMVP-6.5 ( CLKEN pullup to 3.3V with
1.9k ? ) or the selected VID voltage for GMCH ( CLKEN
= GND)—at 1/8 the nominal slew rate set by R TIME :
8 V START
( dV TARGET / dt )
where dV TARGET /dt = 12.5mV/μs x 71.5k ? /R TIME is the
nominal slew rate. The soft-start circuitry does not use a
variable current limit, so full output current is available
immediately. The MAX17528 automatically uses pulse-
skipping mode during soft-start and uses forced-PWM
mode during soft-shutdown, regardless of the SKIP
configuration.
For IMVP-6.5 applications ( CLKEN pullup to 3.3V with
1.9k ? ), the MAX17528 pulls CLKEN low approximately
60μs after reaching PGDIN is pulled high and the con-
troller reaches the 1.1V boot voltage. At the same time,
the MAX17528 slews the output to the selected VID
voltage at the programmed nominal slew rate. PWRGD
becomes high impedance approximately 5ms after
? i
? t
=
V BATT - V OUT
L
I PEAK
CLKEN is pulled low.
For GMCH applications ( CLKEN = GND), PWRGD
becomes high impedance approximately 60μs after
reaching the selected VID voltage.
For automatic startup, the battery voltage should be
present before V CC rises above its UVLO threshold. If
I LOAD = I PEAK /2
the controller attempts to bring the output into regula-
tion without the battery voltage present, the output
undervoltage fault latch disables the controller. The
MAX17528 remains shut down until the fault latch is
0
ON-TIME
TIME
cleared by toggling SHDN or cycling the V CC power
supply below 0.5V.
Figure 8. Pulse-Skipping/Discontinuous Crossover Point
______________________________________________________________________________________
31
相关PDF资料 |
PDF描述 |
|---|---|
| MAX17535ETG+T | IC SMBUS BATT CHARGER 24TQFN |
| MAX1757EAI+T | IC BATTERY CHRG LI+ 28-SSOP |
| MAX17582GTM+T | IC CTLR PWM 2PH IMVP-6.5 48-TQFN |
| MAX1758EAI+T | IC BATTERY CHRG LI+ 28-SSOP |
| MAX1759EUB | IC REG MULTI CONFIG 0.1A 10UMAX |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX17535ETG+ | 功能描述:电池管理 High Frequency SMBus Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX17535ETG+T | 功能描述:电池管理 High Frequency SMBus Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX17535EVKIT+ | 功能描述:电池管理 EVKIT RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX17552ATB+T | 制造商:Maxim Integrated Products 功能描述: |
| MAX1756AAUT | 制造商:Maxim Integrated Products 功能描述:- Cut Tape Product |
发布紧急采购，3分钟左右您将得到回复。