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参数资料
| 型号： | L6996DTR |
| 厂商： | STMICROELECTRONICS |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO24 |
| 封装： | MO-153AD, TSSOP-24 |
| 文件页数： | 3/26页 |
| 文件大小： | 272K |
| 代理商： | L6996DTR |
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L6996
conditions are met contemporarily: the PWM comparator output is low (i.e. the output voltage is below the ref-
erence voltage), the minimum off time is passed and the current limit comparator is not triggered (i.e. the induc-
tor current is under the current limit programmed value). The voltage on the OSC pin must range between 50mV
and 2V to ensure the system linearity.
1.2 Closing the loop
The loop is closed connecting the output voltage to the FB- pin. The FB- pin is linked internally to the comparator
negative pin and the positive pin is connected to the programmed voltage as in Figure 12. When the FB- goes
lower than FB+, the PWM comparator output goes high and sets the flip-flop output, turning on the high side
MOSFET. This condition is latched to avoid noise spike. After the on-time (calculated as described in the pre-
vious section) the system resets the flip-flop and then turns off the high side MOSFET and turns on the low side
MOSFET. Internally the device has more complex logic than a flip-flop to manage the transition in correct way.
For more details refers to the schematic Fig. 1. Because the system implements a valley loop control, the aver-
age output voltage is different from the programmed one as shown in figure 13.
Figure 13. Valley Regulation
Figure 14. Voltage positioning network
The L6996 performs an externally adjustable active droop, achieving a 4m V/A load line slope using a 1.5m
sense resistor without use an external amplifier. Focusing the attention on the control part of the system (Figure
14), it can be considered that the inductor current can revert (the PFM function is deal towards) and the current
Time
Vout
Vref
<Vout>
DC Error Offset
R4
R1
L6996
Vprog
R3
R2
To Vout
Rsense
To inductor
-
+
VFB-
VFB+
COMPARATOR
PWM
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相关代理商/技术参数 |
参数描述 |
|---|---|
| L6997 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:STEP DOWN CONTROLLER FOR LOW VOLTAGE OPERATIONS |
| L6997-28 | 制造商:Johanson Manufacturing 功能描述:TUNING ELEMENT |
| L6997-5 | 制造商:Johanson Manufacturing 功能描述:TUNING ELEMENT; Accessory Type:Tuning Element; For Use With:High Quality Variable Reactance Tuning Microwave Cavities, Filters & other Resonant Structures |
| L6997-9 | 制造商:Johanson Manufacturing 功能描述:TUNING ELEMENT |
| L6997D | 功能描述:DC/DC 开关控制器 Adjustable 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 |
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