- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄358812 > LM1578 (National Semiconductor Corporation) RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS PDF資料下載
參數(shù)資料
| 型號(hào)： | LM1578 |
| 廠商： | National Semiconductor Corporation |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| 中文描述： | 抗輻射高效，5安培開關(guān)穩(wěn)壓器 |
| 文件頁數(shù)： | 8/18頁 |
| 文件大?。?/td> | 1037K |
| 代理商： | LM1578 |
Applications Information
(Continued)
C.L. SENSE VOLTAGE MULTIPLICATION
When a larger sense resistor value is desired, the voltage di-
vider network, consisting of R1 and R2, may be used. This
effectively multiplies the sense voltage by (1 + R1/R2). Also,
R1 can be replaced by a diode to increase current limit
sense voltage to about 800 mV (diode V
f
+ 110 mV).
UNDER-VOLTAGE LOCKOUT
Under-voltage lockout is accomplished with few external
components. When V
becomes lower than the zener
breakdown voltage, the output transistor is turned off. This
occurs because diode D1 will then become forward biased,
allowing resistor R3 to sink a greater current from the
non-inverting input than is sunk by the parallel combination
of R1 and R2 at the inverting terminal. R3 should be one-fifth
of the value of R1 and R2 in parallel.
MAXIMUM DUTY CYCLE LIMITING
The maximum duty cycle can be externally limited by adjust-
ing the charge to discharge ratio of the oscillator capacitor
with a single external resistor. Typical values are 50 μA for
the charge current, 450 μA for the discharge current, and a
voltage swing from 200 mV to 750 mV. Therefore, R1 is se-
lected for the desired charging and discharging slopes and
C1 is readjusted to set the oscillator frequency.
DUTY CYCLE ADJUSTMENT
When manual or mechanical selection of the output transis-
tor’s duty cycle is needed, the cirucit shown below may be
used. The output will turn on with the beginning of each os-
cillator cycle and turn off when the current sunk by R2 and
R3 from the non-inverting terminal becomes greater than the
current sunk from the inverting terminal.
With the resistor values as shown, R3 can be used to adjust
the duty cycle from 0% to 90%.
When the sum of R2 and R3 is twice the value of R1, the
duty cycle will be about 50%. C1 may be a large electrolytic
capacitor to lower the oscillator frequency below 1 Hz.
DS008711-18
FIGURE 5. Current Limit Transient Suppressor,
V
in
Referred
DS008711-19
FIGURE 6. Current Limit Sense Voltage Multiplication,
Ground Referred
DS008711-20
FIGURE 7. Current Limit Sense Voltage Multiplication,
V
in
Referred
DS008711-22
FIGURE 8. Under-Voltage Lockout
DS008711-21
FIGURE 9. Maximum Duty Cycle Limiting
www.national.com
8
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM1578A | CAP 100UF 50V ELECT TG SMD |
| LM158AFK | DUAL OPERATIONAL AMPLIFIERS |
| LM158APT | OP-AMP|DUAL|BIPOLAR|TSSOP|8PIN|PLASTIC |
| LM158AN | Voltage-Feedback Operational Amplifier |
| LM158AJ-QMLV | Voltage-Feedback Operational Amplifier |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM1578A | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Switching Regulator |
| LM1578AH/883 | 制造商:Rochester Electronics LLC 功能描述: |
| LM1578H | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Mode SMPS Controller |
| LM158 | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Low power dual operational amplifiers |
| LM158 MD8 | 制造商:Texas Instruments 功能描述:LINEAR IC-NON VMI |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。