參數(shù)資料
型號: L5985TR
廠商: 意法半導(dǎo)體
英文描述: 2A step-down switching regulator
中文描述: 第2A降壓型開關(guān)穩(wěn)壓器
文件頁數(shù): 10/36頁
文件大?。?/td> 757K
代理商: L5985TR
L5985
Functional description
10/36
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 (V
REF
) of the
Error Amplifier. So the output voltage slew rate is:
Equation 1
where SR
VREF
is the slew rate of the non-inverting input and R1, R2 is the resistor divider to
regulate the output voltage (see
Figure 7
). The soft-start stair case consists of 64 steps of
9.5mV each one, from 0V to 0.6V. 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 250kHz the SS
TIME
is 8ms.
SR
OUT
SR
VREF
1
R2
-------
+
=
SS
TIME
Fsw
-----------------
=
相關(guān)PDF資料
PDF描述
L5991 PRIMARY CONTROLLER WITH STANDBY
L5991A PRIMARY CONTROLLER WITH STANDBY
L5991AD PRIMARY CONTROLLER WITH STANDBY
L5991D PRIMARY CONTROLLER WITH STANDBY
L5993 CONSTANT POWER CONTROLLER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L5986 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.5 A buck switching regulator RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
L5986A 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.5 A STEP-DOWN SWITCH REG RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
L5986ATR 功能描述:直流/直流開關(guān)調(diào)節(jié)器 Step-down switch regulator, 2.5A RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
L5986TR 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.5 A Step-down Switch Regulator RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
L5987 功能描述:直流/直流開關(guān)調(diào)節(jié)器 3 A buck switching regulator RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5