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參數資料
| 型號： | FAN7680N |
| 廠商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分類： | 電源管理 |
| 英文描述： | PC Power Supply Outputs Monitoring IC |
| 中文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDIP8 |
| 封裝： | DIP-8 |
| 文件頁數： | 11/16頁 |
| 文件大小： | 234K |
| 代理商： | FAN7680N |
FAN7680
11
Application Information
Power Good(PGO) and Power Good Delay
A PC power supply is commonly designed to provide the motherboard with a power good signal, which is defined by the com-
puter manufactures. If the +3.3V, +5V, and +12V outputs are above the undervoltage threshold limit, the PC power supply
makes the power good signal high after some delay. At this time the power supply should be able to provide enough power to
assure continuous operation within the specification. Conversely, when one of the +3.3V, +5V, or +12V outputs falls below the
undervoltage threshold or rise above the overvoltage threshold, or when main power has been turned off for a sufficiently long
time so that power supply operation is no longer assured, a PGO signal will be a low state.
The AC input, power good(PGO), remote on/off(PSON), and +3.3V/+5V/+12V supply rails are shown in figure 1.
Although there is no requirement for specific timing parameters, the following signal timings are recommended :
-T1(Power On Time) : T1 <
500ms
-T2(Rise Time) : 0.1ms
≤
T2
≤
20ms
-T3(PGO Delay) : 100ms < T3 <500ms
-T4(PGO Delay Risetime) : T4
≤
10ms
-T5(AC Loss to PGO Hold-Up Time) : T5
≥
16ms
-T6(Power Down Warning) : T6
≥
1ms
Furthermore, motherboards should be designed to comply with the above recommended timing range. If timings other than
these are implemented or required, that information should be clearly specified.
The FAN7680 provides a power good(PGO) signal for the +3.3V, +5V and +12V(Vcc) supply voltage rails and a separate
power good input(PGI). An internal delay circuit is used to generate a 300ms power good delay.
If voltages at PGI(+1.2V), VS33(+3.3V), VS5(+5V), and Vcc(+12V) rise above the undervoltage threshold, the open drain
power good output(PGO) will go high after a delay of 300ms. When the PGI voltage or any of +3.3V, +5V, and +12V rails
drops below the undervoltage threshold, the PGO signal will be disabled immediately.
Power Supply Remote On/Off(PSON) and Fault Protect Output(FPO)
Since the latest personal computer generation focuses on easy turn on and power saving functions, a PC power supply will
require two characteristics. One is a dc power supply remote on/off function; the other is standby voltage to achieve very low
power consumption of the PC power supply. Thus, the main power needs to be shut down.
The power supply remote on/off(PSON) is an active-low signal that turns on all of the main power rails including the +3.3V,
+5V, and +12V power rails. When this signal is held high by the PC motherboard or left open circuited, the signal of the fault
protect output(FPO) also goes high. Thus, the main power rails can not deliver power and are held at 0V.
When the FPO signal is held high due to an fault condition, the fault status will be latched and the outputs of the main power
rails can not deliver power and are held at 0V. Toggling the PSON input signal from low to high will reset the fault protection
latch. During this fault condition only the standby power is not affected.
When the PSON input signal goes from high to low or low to high, the 38ms debounce block will be active to avoid that a
glitch on the PSON input may disable/enable the FPO output. When the PSON is set low, the undervoltage function is disabled
T1
T5
T5
T4
T3
T2
PGO
+12VDC
+5VDC
+3.3VDC
PSON
VAC
95%
10%
Figure 1. Timing Diagram
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| FAN7685 | PC Power Supply Output Monitoring IC |
| FAN7685M | PC Power Supply Output Monitoring IC |
| FAN7685MX | PC Power Supply Output Monitoring IC |
| FAN7685N | PC Power Supply Output Monitoring IC |
| FAN7686 | ECONOLINE: REC3-S_DRW(Z)/H4,H6 - Safety standards and approval: EN 60950 certified, rated for 250VAV (LVD test report)- Applied for Ul 1950 Component Recognised Certification- 3W DIP Package- 4kVDC & 6kVDC Isolation- Regulated Output- Continuous Short Circiut Protection Auto-Restarting |
相關代理商/技術參數 |
參數描述 |
|---|---|
| FAN7685 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:PC Power Supply Output Monitoring IC |
| FAN7685M | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:PC Power Supply Output Monitoring IC |
| FAN7685MX | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:PC Power Supply Output Monitoring IC |
| FAN7685N | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:PC Power Supply Output Monitoring IC |
| FAN7686 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:PC Power Supply Output Monitoring IC |
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