参数资料
型号: L5983
厂商: STMICROELECTRONICS
元件分类: 稳压器
英文描述: 1.5 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO8
封装: 3 X 3 MM, 1.08 MM HEIGHT, LEAD FREE, VFQFPN-8
文件页数: 2/37页
文件大小: 832K
代理商: L5983
Functional description
L5983
10/37
Doc ID 13005 Rev 6
4.2
Soft-start
The soft-start is essential to assure correct and safe start up of the step-down converter. It
avoids inrush current surge and makes the output voltage increases monothonically.
The soft-start is performed by a staircase ramp on the non-inverting input (VREF) of the error
amplifier. So the output voltage slew rate is:
Equation 1
where SRVREF is the slew rate of the non-inverting input while R1 and R2 the resistor divider
to regulate the output voltage (see Figure 7). The soft-start stair case consists of 64 steps of
9.5 mV each one, from 0 V to 0.6 V. The time base of one step is of 32 clock cycles. So the
soft-start time and then the output voltage slew rate depend on the switching frequency.
Figure 7.
Soft-start scheme
Soft-start time results:
Equation 2
For example with a switching frequency of 250 kHz the SSTIME is 8 ms.
SR
OUT
SR
VREF
1
R1
R2
--------
+
=
SS
TIME
32 64
Fsw
-----------------
=
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L5983TR 1.5 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO8
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相关代理商/技术参数
参数描述
L5983_08 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:1.5 A step-down switching regulator
L5983TR 功能描述:直流/直流开关调节器 1.5a Step-Down Switching Reg 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
L5985 功能描述:直流/直流开关调节器 2A STEP-DOWN SWITCH REGULATOR 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
L5985_08 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:2 A step-down switching regulator
L5985TR 功能描述:直流/直流开关调节器 2a Step-Down Switching Reg 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