- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄361092 > NCP1562A (ON SEMICONDUCTOR) High Performance Active Active Clamp/Reset PWM Controller Controller(高性能有效Clamp/Reset PWM控制器) PDF資料下載
參數(shù)資料
| 型號： | NCP1562A |
| 廠商： | ON SEMICONDUCTOR |
| 英文描述： | High Performance Active Active Clamp/Reset PWM Controller Controller(高性能有效Clamp/Reset PWM控制器) |
| 中文描述： | 高性能主動有源鉗位/復(fù)位PWM控制器控制器（高性能有效鉗位/復(fù)位的PWM控制器） |
| 文件頁數(shù)： | 19/26頁 |
| 文件大小： | 277K |
| 代理商： | NCP1562A |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁當(dāng)前第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁
NCP1562A, NCP1562B
http://onsemi.com
19
(patent pending). This architecture allows both the UV and
OV levels to be set independently. Both the UV and OV
detectors have a 100 mV hysteresis.
The line voltage is sampled using a resistor divider as
shown in Figure 42.
-
+
OV Comparator
V
OVCOMP
3.0 V
+
-
-
+
UV Comparator
V
UVCOMP
2.0 V
+
-
-
+
2.5 V
+
-
UVOV
C
UVOV
R1
R2
V
in
I
offset(UVOV)
Figure 42. Line UVOV Detectors
A UV condition exists if the UVOV voltage is below
V
UV
, typically 2.0 V. The ratio of R1 and R2 determines the
UV turn threshold. Once the UVOV voltage exceeds 2.5 V,
an internal current source (I
offset(UVOV)
) sinks 50 A into
the UVOV pin. This will clamp the UVOV voltage at 2.5 V
while the current across R1 is less than I
offset(UVOV)
. If the
input voltage continues to increase, the 50 A source will
be overridden and the voltage at the UVOV pin will
increase. An OV condition exists if the UVOV voltage
exceeds V
OV
, typically 3.0 V. Figure 43 shows the
relationship between UVOV and V
in
.
Figure 43. UVOV Detectors Typical Waveforms
Time
V
U
V
i
V
OVCOMP
V
UVCOMP
V
UVOV
While the internal current source is disabled, the UVOV
voltage is solely determined by the ratio of R1 and R2. The
input voltage at which the converter turns ON is given by
Equation 1. Once the internal current source is enabled, the
absolute value of R1 together with the ratio of R1 and R2
determine the turn OFF threshold as shown in Equation 2.
Vin(UV)
VUV
(R1
R2)
R2
(eq. 1)
Vin(OV)
VOV
(R1
R2)
R2
(Ioffset(UVOV)
R1)
(eq. 2)
The undervoltage threshold is trimmed during
manufacturing to obtain
3% accuracy allowing a tighter
power stage design.
Once the line voltage is within the operating range, and
V
AUX
reaches V
AUX(on)
, the outputs are enabled and a
soft-start sequence commences. If a UV or OV fault is
detected afterwards, the converter enters a soft-stop mode.
A small capacitor is required (>1000 pF) from the
UVOV pin to GND to prevent oscillation of the UVOV pin
and filter line transients.
Line Feedforward
The NCP1562 incorporates line feedforward (FF) to
limit the maximum volt-second product. It is the line
voltage times the ON time. This limit prevent saturation of
the transformer in forward and flyback topologies. Another
advantage of feedforward is a controller frequency gain
independent of line voltage. A constant gain facilitates
frequency compensation of the converter.
Feedforward is implemented by generating a ramp
proportional to V
in
and comparing it to the error signal. The
error signal solely controls the duty cycle while the input
voltage is fixed. If the line voltage changes, the FF Ramp
slope changes and duty cycle is immediately adjusted instead
of waiting for the change to propagate around the feedback
loop and be reflected back on the error signal.
The FF Ramp is generated with an R-C (R
FF
C
FF
) divider
from the input line as shown in Figure 44. The divider is
selected such that the FF Ramp reaches 3.0 V in the desired
maximum ON time. The FF Ramp terminates by
effectively grounding C
FF
during the converter OFF time.
This can be triggered by the FF Ramp reaching 3.0 V, or
any other condition that limits the duty cycle.
To PWM and VS
Comparators
FF Reset
I
FF(D)
V
in
R
FF
I
RFF
C
FF
FF
3 V
0 V
T
t
on
Figure 44. Feed Forward Ramp Generation
The FF pin is effectively grounded during power or
during standby mode to prevent the FF pin from charging
up to V
in
.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| NCP1562B | High Performance Active Active Clamp/Reset PWM Controller Controller(高性能有效Active Clamp/Reset PWM控制器) |
| NCP1729 | Switched Capacitor Voltage Inverter |
| NCP1729SN35T1 | Switched Capacitor Voltage Inverter |
| NCP1729SN35T1G | Switched Capacitor Voltage Inverter |
| NCP21WB473 | for Surface Mounting Application |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| NCP1562A WAF | 制造商:ON Semiconductor 功能描述: |
| NCP1562ADBR2G | 功能描述:電壓模式 PWM 控制器 HI PERF RESET PWM CONTLR RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
| NCP1562ADR2G | 功能描述:電壓模式 PWM 控制器 HI PERF RESET PWM CONTLR RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
| NCP1562BDBR2G | 功能描述:電壓模式 PWM 控制器 HI PERF RESET PWM CONTLR RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
| NCP1562BDR2G | 功能描述:電壓模式 PWM 控制器 HI PERF RESET PWM CONTLR RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。