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参数资料
| 型号： | FA5515P |
| 厂商： | FUJI ELECTRIC CO LTD |
| 元件分类： | 稳压器 |
| 英文描述： | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDIP8 |
| 封装： | DIP-8 |
| 文件页数： | 22/22页 |
| 文件大小： | 260K |
| 代理商： | FA5515P |
FA551X
9
■ Description of each circuit
1.
Oscillator
The oscillator generates a triangular waveform by charging and
discharging the built-in capacitor. A desired oscillation
frequency can be set by the value of the resistor connected to
the RT pin (See Figure 1).
The built-in capacitor voltage oscillates between about 3V and
1V, with almost the same charging and discharging gradients
(Figure 2). You can set the desired oscillation frequency by
changing the gradients using the resistor connected to the RT
pin. (Large RT=Low frequency, small RT=High frequency)
The relationship between RT and the oscillation frequency is
approximately given by:
The oscillator waveform cannot be observed from the outside
because the oscillator output is not pinned out. The oscillator
output is connected to a PWM comparator.
2. PWM comparator
The PWM comparator has four inputs as shown in Figure 3.
Oscillator output
is compared with CS pin voltage
, FB pin
voltage
, and DT voltage
. The lowest of three inputs
,
, and
has priority and is compared with oscillator output
.
While the voltage is lower than the oscillator output, the
comparator output is high. While the voltage is higher than the
oscillator output, the PWM comparator output is low (see Figure
4). The IC OUT pin voltage is high while the PWM comparator
output is low. When the IC is powered up, CS pin voltage
controls soft start operation. The output pulse then begins to
widen gradually. During normal operation, the output pulse
width is determined within the maximum duty cycle (FA5510/14:
46%, FA5511/15: 70%) set by DT voltage
under the
condition set by FB pin voltage
, to stabilize the output
voltage.
Fig. 1
Oscillator
Fig. 2
Oscillator output
Fig. 3
PWM comparator
Fig. 4
PWM comparator timing chart
RT
RT
1
OSC
3V
1V
RT=Small
RT=Large
DT voltage
FB pin voltage
PWM comparator
output
CS pin voltage
Oscillator
output
FB pin voltage
PWM comparator
output
(4.0V)
OUT pin voltage
DT voltage
Oscillator output
CS pin voltage
fOSC: Oscillation frequency [kHz]
RT:
Timing resistance [k
]
fOSC
4880
[kHz]
RT + 1.4
RT
4880
– 1.4 [k
]
fOSC
........................................................ (1)
........................................................ (2)
相关PDF资料 |
PDF描述 |
|---|---|
| FA5514N | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO8 |
| FA5515N | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO8 |
| FA5510N | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO8 |
| FA5511P | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDIP8 |
| FA5514P | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDIP8 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| FA5515P-D1 | 制造商:Fuji Electric 功能描述: |
| FA551X | 制造商:未知厂家 制造商全称:未知厂家 功能描述:CMOS IC For Switching Power Supply Control |
| FA5526 | 制造商:FUJI 制造商全称:Fuji Electric 功能描述:Fuji Switching Power Control IC |
| FA5527 | 制造商:FUJI 制造商全称:Fuji Electric 功能描述:Fuji Switching Power Control IC |
| FA5527P-A2 | 制造商:Fuji Electric 功能描述: |
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