參數(shù)資料
型號(hào): MB3785
廠商: Fujitsu Limited
英文描述: Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)
中文描述: 開關(guān)穩(wěn)壓器控制器(4通道加高精度,高頻率功能)
文件頁(yè)數(shù): 21/29頁(yè)
文件大?。?/td> 293K
代理商: MB3785
21
MB3785A
I
METHOD OF SETTING THE DEAD TIME AND SOFT START
1.
Dead Time
When the device is set for step-up inverted output based on the flyback method, the output transistor is fixed to a
full-on state (ON-duty = 100 %) at power switch-on. To prevent this problem, you may determine the voltages on
the DTC terminals (pins 4, 9, 28, and 33) from the V
REF
voltage so you can easily set the output transistor’s dead
time (maximum ON-duty) independently for each channel as shown below.
(1) CH1 and CH2 Channels
When the voltage on the DTC terminals (pins 4 and 9) is higher than the triangular-wave output voltage from the
oscillator, the output transistor turns off. The dead time calculation formula assuming that triangular-wave amplitude
0.6 V and triangular-wave minimum voltage
1.3 V is given below.
When you do not use these DTC terminals, connect them to GND.
(2) CH3 and CH4 Channels
When the voltage on the DTC terminals (pins 28 and 33) is lower than the triangular-wave output voltage from the
oscillator, the output transistor turns off. The dead time calculation formula assuming that traingular-wave amplitude
0.6 V and triangular-wave maximum voltage
1.9 V is given below.
When you do not use these DTC terminals, connect them to V
REF
.
Duty (OFF) =
×
100 [%], V
dt
=
×
V
REF
V
dt
– 1.3
0.6
R
1
+ R
2
R
2
Figure 9. When Using DTC to Set Dead Time
Figure 10. When Not Using DTC
V
REF
R
1
R
2
DTC1
(DTC2)
Vdt
19
DTC1
(DTC2)
Duty (OFF)
×
100 [%], V
dt
=
×
V
REF
1.9 –V
dt
0.6
R
1
+ R
2
R
2
相關(guān)PDF資料
PDF描述
MB3785A Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)
MB3785APFV Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)
MB3788 RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
MB3789 RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
MB3789PFV RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MB3785A 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)
MB3785A_03 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)
MB3785APFV 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)
MB3785APFV-G-BND(E1) 制造商:Fujitsu 功能描述:
MB3788 制造商:FUJITSU 制造商全稱:Fujitsu Component Limited. 功能描述:SWITCHING REGULATOR CONTROLLER