- 您现在的位置：买卖IC网 > PDF目录1839 > MAX1717EEG+ (Maxim Integrated Products)IC REG CTRLR BUCK PWM CM 24-QSOP PDF资料下载
参数资料
| 型号： | MAX1717EEG+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 14/33页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 24-QSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1MHz |
| 占空比： | 100% |
| 电源电压： | 4.5 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： | 24-SSOP（0.154"，3.90mm 宽） |
| 包装： | 管件 |
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页当前第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页第31页第32页第33页
Dynamically Adjustable, Synchronous
Step-Down Controller for Notebook CPUs
Table 2. Component Suppliers
MANUFACTURER USA PHONE
FACTORY FAX
[Country Code]
the low-side switch current is below the current-limit
threshold, and the minimum off-time one-shot has timed
out.
Coilcraft
Dale-Vishay
International Rectifier
Kemet
Panasonic
Sumida
Taiyo Yuden
847-639-6400
402-564-3131
310-322-3331
408-986-0424
714-373-7939
847-956-0666
408-573-4150
[1] 847-639-1469
[1] 402-563-6418
[1] 310-322-3332
[1] 408-986-1442
[1] 714-373-7183
[81] 3-3607-5144
[1] 408-573-4159
On-Time One-Shot (TON)
The heart of the PWM core is the one-shot that sets the
high-side switch on-time. This fast, low-jitter, adjustable
one-shot includes circuitry that varies the on-time in
response to battery and output voltage. The high-side
switch on-time is inversely proportional to the battery
voltage as measured by the V+ input, and proportional
to the output voltage. This algorithm results in a nearly
constant switching frequency despite the lack of a
Detailed Description
+5V Bias Supply (V CC and V DD )
The MAX1717 requires an external +5V bias supply in
addition to the battery. Typically, this +5V bias supply
is the notebook’s 95% efficient +5V system supply.
Keeping the bias supply external to the IC improves
efficiency and eliminates the cost associated with the
+5V linear regulator that would otherwise be needed to
supply the PWM circuit and gate drivers. If stand-alone
capability is needed, the +5V supply can be generated
with an external linear regulator.
The +5V bias supply must provide V CC (PWM con-
troller) and V DD (gate-drive power), so the maximum
current drawn is:
I BIAS = I CC + f (Q G1 + Q G2 ) = 10mA to 40mA (typ)
where I CC is 700μA (typ), f is the switching frequency,
and Q G1 and Q G2 are the MOSFET data sheet total
gate-charge specification limits at V GS = 5V.
V+ and V DD can be tied together if the input power
source is a fixed +4.5V to +5.5V supply. If the +5V bias
supply is powered up prior to the battery supply, the
enable signal (SKP/ SDN going from low to high or
open) must be delayed until the battery voltage is pre-
sent to ensure startup.
Free-Running, Constant On-Time PWM
Controller with Input Feed-Forward
The Quick-PWM control architecture is a pseudofixed-
fixed-frequency clock generator. The benefits of a con-
stant switching frequency are twofold: first, the frequency
can be selected to avoid noise-sensitive regions such
as the 455kHz IF band; second, the inductor ripple-cur-
rent operating point remains relatively constant, resulting
in easy design methodology and predictable output
voltage ripple.
On-Time = K (V OUT + 0.075V) / V IN
where K is set by the TON pin-strap connection and
0.075V is an approximation to accommodate the expect-
ed drop across the low-side MOSFET switch (Table 3).
The on-time one-shot has good accuracy at the operating
points specified in the Electrical Characteristics (±10% at
200kHz and 300kHz, ±12% at 550kHz and 1000kHz).
On-times at operating points far removed from the condi-
tions specified in the Electrical Characteristics can vary
over a wide range. For example, the 1000kHz setting will
typically run about 10% slower with inputs much greater
than +5V due to the very short on-times required.
On-times translate only roughly to switching frequencies.
The on-times guaranteed in the Electrical Character-
istics are influenced by switching delays in the external
high-side MOSFET. Resistive losses, including the
inductor, both MOSFETs, output capacitor ESR, and PC
board copper losses in the output and ground tend to
raise the switching frequency at higher output currents.
Table 3. Approximate K-Factors Errors
frequency, constant-on-time current-mode type with volt-
age feed-forward (Figure 2). This architecture relies on
the output filter capacitor’s ESR to act as the current-
sense resistor, so the output ripple voltage provides the
PWM ramp signal. The control algorithm is simple: the
TON K
SETTING FACTOR
(kHz) (μs)
200 5
APPROXIMATE MIN RECOMMENDED
K-FACTOR V BATT AT V OUT = 1.6V
ERROR (%) (V)
±10 2.1
high-side switch on-time is determined solely by a one-
shot whose period is inversely proportional to input volt-
age and directly proportional to output voltage. Another
one-shot sets a minimum off-time (400ns typ). The on-
300
550
1000
3.3
1.8
1.0
±10
±12.5
±12.5
2.3
3.2
4.5
time one-shot is triggered if the error comparator is low,
14
______________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| MAX1720EUT | IC REG SWITCHD CAP INV ADJ 6TSOP |
| MAX1721EUT-T | IC REG SWITCHED CAP INV SOT23-6 |
| MAX1724EZK50-T | IC REG BST SYNC 5V .15A TSOT23-5 |
| MAX1725EUK+T | IC REG LDO ADJ 20MA SOT23-5 |
| MAX1729EUB | IC REG BUCK BST ADJ 2.5MA 10UMAX |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1717EEG+ | 功能描述:DC/DC 开关控制器 Adj Synchronous Step-Down RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1717EEG+C71058 | 功能描述:DC/DC 开关控制器 Step-Down Controller for Notebook CPU RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1717EEG+T | 功能描述:DC/DC 开关控制器 Adj Synchronous Step-Down RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1717EEG-C71058 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX1717EEG-T | 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
发布紧急采购，3分钟左右您将得到回复。