- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄375327 > AN8026 (PANASONIC CORP) Self-excited RCC pseudo-resonance type AC-DC switching power supply control IC PDF資料下載
參數(shù)資料
| 型號(hào)： | AN8026 |
| 廠商： | PANASONIC CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Self-excited RCC pseudo-resonance type AC-DC switching power supply control IC |
| 中文描述： | 1 A SWITCHING CONTROLLER, PSIP9 |
| 封裝： | PLASTIC, SIP-9 |
| 文件頁數(shù)： | 8/12頁 |
| 文件大?。?/td> | 125K |
| 代理商： | AN8026 |
8
AN8026
Voltage Regulators
I
Application Notes (continued)
[2] Operation descriptions (continued)
4. Pseudo-resonance operation (Power MOSFET turn-on delay circuit)
For the AN8026, the pseudo-resonance operation becomes possible by making connection as shown in figure 5.
The C7 is a resonance capacitor, and the R9 and C9 constitute the delay circuit for regulating the turn-on of power
MOSFET. When the power MOSFET is turned off, the voltage generated in the drive coil is inputted to the TDL
(time delay) terminal (pin 1) through the R9 and C9. While high-level signal (higher than threshold voltage 0.7 V)
is inputted, the power MOSFET remains off. Also, the TDL terminal has the high/low-side clamping capability.
The upper limit of clamping voltage is 2.8 V (typical) (when sink current:
3 mA) and the lower limit of clamping
voltage is approximately 0 V (typical) (when source current: 3 mA). The off-period of the power MOSFET is
determined by the following periods whichever longer: the period until the TDL terminal input voltage becomes
a voltage lower than the threshold voltage as the transformer started the resonance operation and the drive coil
voltage drops, and the minimum off-period T
OFF(min)
of the internal oscillation circuit. (Refer to description on the
oscillation circuit.)
As for the turn-on of power MOSFET, determine the delay time by selecting the constant of the R9 and C9 so
that it turns on at 1/2 cycle of the resonance frequency.
In a simplified method, select so that the voltage waveform turns on at zero voltage. (Refer to figure 6.)
The approximate value of resonance frequency can be obtained by the following equations:
f
SYNC
=
1
[Hz]
C: resonance capacitance
L: inductance of transformer's primary coil
2
π √
L · C
Therefore, the turn-on delay time t
pd(ON)
for turning on the power MOSFET at 1/2 cycle of resonance frequency
is as follows:
t
pd(ON)
= π √
L · C
[s]
5. Notes on R9 and C9 selection
If too high resistance is selected for the R9, the TDL terminal voltage exceeds the threshold voltage at the start
of power supply because there is the current (maximum
52
μ
A) flowing out of the TDL terminal (pin 1). In such
a case, the power MOSFET remains in the off-state and the state in which the operation can not be started may
occur (start failure). On the other hand, if too low resistance is selected for the R9, the current flowing into the
TDL terminal after the start of power supply exceeds the maximum rating value and there is a possibility of causing
malfunction (destruction in the worst case). It is recommended that about 8 k
to 10 k
be selected for the R9
though it depends on the supply voltage from the bias coil.
Therefore, adjust t
pd(ON)
with C9 after converting from the inductance of transformer being used and the
resonance capacitance.
Figure 5
V
CC
TDL
V
OUT
V
IN
After AC rectification
R1
C8
SBD
V
P
I
D
R7
C9
R9
C7
SBD
t
pd
V
P
V
IN
V
DS
0 V
0 V
0 V
0.7 V
V
TDL
I
D
V
TDL
2.8 V typ.
Figure 6
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AN8027 | AC-DC switching power supply control IC with standby mode |
| AN8037 | AC-DC switching power supply control IC with standby mode |
| AN8028 | Self-excited RCC pseudo-resonance type AC-DC switching power supply control IC |
| AN8029 | Self-excited RCC pseudo-resonance type AC-DC switching power supply control IC |
| AN8031 | Active filter control IC |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AN8027 | 制造商:PANASONIC 制造商全稱:Panasonic Semiconductor 功能描述:AC-DC switching power supply control IC with standby mode |
| AN-8027 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:PFC+PWM Combination Controller |
| AN8027/AN8037 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:AN8027. AN8037 - AC-DC switching power supply control IC with standby mode |
| AN8028 | 制造商:PANASONIC 制造商全稱:Panasonic Semiconductor 功能描述:Self-excited RCC pseudo-resonance type AC-DC switching power supply control IC |
| AN8029 | 制造商:Panasonic Industrial Company 功能描述:IC PANASONIC |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。