- 您现在的位置：买卖IC网 > PDF目录15138 > MAX1993ETG+ (Maxim Integrated Products)IC REG CTRLR BUCK PWM CM 24-TQFN PDF资料下载
参数资料
| 型号： | MAX1993ETG+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 27/36页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 24-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 75 |
| 系列： | Quick-PWM™ |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 600kHz |
| 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-WFQFN 裸露焊盘 |
| 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页当前第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页
Quick-PWM Step-Down Controllers with Inductor
Saturation Protection and Dynamic Output Voltages
Table 7. Current-Sense Configurations
METHOD
A) Output Current-Sense Resistor
CURRENT-SENSE
ACCURACY
High
INDUCTOR SATURATION
PROTECTION
Allowed
(highest accuracy)
CURRENT-SENSE POWER LOSS
(EFFICIENCY)
R SENSE x I OUT2
? × R SENSE OUT
× I
B) Low-Side Current-Sense Resistor
C) Low-Side MOSFET On-Resistance
D) Equivalent Inductor DC Resistance
High
Low
Low
Not allowed
(LSAT = GND)
Not allowed
(LSAT = GND)
Allowed
? V OUT ?
?
? 1 ? V IN ?
No additional loss
No additional loss
2
The overshoot during a full-load to no-load transient due
to stored inductor energy can be calculated as:
Most applications employ a valley current-sense volt-
age (V LIM(VAL) ) of 50mV to 100mV, so the sense resis-
V SOAR
≈
( Δ I LOAD ( MAX ) )
2 C OUT V OUT
2
L
tor can be determined by:
R SENSE = V LIM(VAL) / I LIM(VAL)
For the best current-sense accuracy and overcurrent
I LIM ( VAL ) > I LOAD ( MAX ) ? ? ?
? ?
Setting the Current Limit
The minimum current-limit threshold must be great
enough to support the maximum load current when the
current limit is at the minimum tolerance value. The val-
ley of the inductor current occurs at I LOAD(MAX) minus
half the ripple current; therefore:
? I LOAD (MAX) LIR ?
2
where I LIM(VAL) equals the minimum valley current-limit
threshold voltage divided by the current-sense resis-
tance (R SENSE ). For the 50mV default setting, the mini-
mum valley current-limit threshold is 40mV.
Connect ILIM to V CC for a default 50mV valley current-
limit threshold. In adjustable mode, the valley current-
limit threshold is precisely 1/10th the voltage seen at
ILIM. For an adjustable threshold, connect a resistive
divider from REF to analog ground (GND) with ILIM
connected to the center tap. The external 250mV to 2V
adjustment range corresponds to a 25mV to 200mV
valley current-limit threshold. When adjusting the cur-
rent limit, use 1% tolerance resistors and a divider cur-
rent of approximately 10μA to prevent significant
inaccuracy in the valley current-limit tolerance.
The current-sense method (Figure 10) and magnitude
determine the achievable current-limit accuracy and
power loss (Table 7). Typically, higher current-sense
voltage limits provide tighter accuracy but also dissi-
pate more power.
protection, use a 1% tolerance current-sense resistor
between the inductor and output as shown in Figure
10a. This configuration constantly monitors the inductor
current, allowing accurate valley current-limiting and
inductor saturation protection.
For low output voltage applications that require higher
efficiency, the current-sense resistor can be connected
between the source of the low-side MOSFET (N L ) and
power ground (Figure 10b) with CSN connected to the
drain of N L and CSP connected to power ground. In
this configuration, the additional current-sense resis-
tance only dissipates power when N L is conducting
current. Inductor saturation protection must be dis-
abled with this configuration (LSAT = GND) because
the inductor current is only properly sensed when the
low-side MOSFET is turned on.
For high-power applications that do not require high-
accuracy current sensing or inductor saturation protec-
tion, the MAX1992/MAX1993 can use the low-side
MOSFET’s on-resistance as the current-sense element
(R SENSE = R DS(ON) ) by connecting CSN to the drain of
N L and CSP to the source of N L (Figure 10c). Use the
worst-case maximum value for R DS(ON) from the
MOSFET data sheet, and add some margin for the rise
in R DS(ON) with temperature. A good general rule is to
allow 0.5% additional resistance for each °C of temper-
ature rise. Inductor saturation protection must be dis-
abled with this configuration (LSAT = GND) because
the inductor current is properly sensed only when the
low-side MOSFET is turned on.
______________________________________________________________________________________
27
相关PDF资料 |
PDF描述 |
|---|---|
| SLP392M050E1P3 | CAP ALUM 3900UF 50V 20% SNAP |
| ECC40DRTH | CONN EDGECARD 80POS DIP .100 SLD |
| MAX1744EUB/V+ | IC REG CTRLR BUCK PWM 10-UMAX |
| SLPX681M180C3P3 | CAP ALUM 680UF 180V 20% SNAP |
| EBC65DRTF | CONN EDGECARD 130PS DIP .100 SLD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1993ETG+ | 功能描述:电压模式 PWM 控制器 Step-Down w/Inductor RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1993ETG+T | 功能描述:电压模式 PWM 控制器 Step-Down w/Inductor RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1993ETG+TG40 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX1993ETG-T | 功能描述:电压模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1993EVKIT | 制造商:Maxim Integrated Products 功能描述:EVALUATION KIT FOR THE MAX1992 MAX1993 - Bulk |
发布紧急采购，3分钟左右您将得到回复。