參數(shù)資料
型號(hào): UC1827JTR-1
廠商: TEXAS INSTRUMENTS INC
元件分類: 穩(wěn)壓器
英文描述: 1 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, CDIP24
封裝: CERAMIC, DIP-24
文件頁(yè)數(shù): 14/16頁(yè)
文件大小: 314K
代理商: UC1827JTR-1
www.ti.com
APPLICATION INFORMATION
+
RT
CT
SYNC
S
R
VREF
2.5 V
OSCILLATOR
VREF
10 kW
1.4 V
2.5 V
2.9 V
0.5 V
RT
CT
VDG99086
CIRCUIT BLOCK DESCRIPTION
PWM Oscillator
I
RT +
2.5 V
R
RT
(1)
UC1827-1, UC1827-2
UC2827-1, UC2827-2
UC3827-1, UC3827-2
SLUS365A – APRIL 1999 – REVISED AUGUST 2005
Figure 1. Oscillator Block With External Connections
The oscillator block diagram with external connections is shown in Equation 1. A resistor (RT) connected to pin
RT sets the linear charge current:
The timing capacitor (CCT) is linearly charged with the charge current forcing the OSC pin to charge to a 3.4 V
threshold. After exceeding this threshold, the RS flip-flop is set driving CLKSYN high and RDEAD low which
discharges CCT. CT continues to discharge until it reaches a 0.5 V threshold and resets the RS flip-flop which
repeats the charging sequence as shown in Figure 2
As shown in Figure 3, several oscillators are synchronized to the highest free running frequency by connecting
100 pF capacitors in series with each CLKSYN pin and connecting the other side of the capacitors together
forming the CLKSYN bus. The CLKSYN bus is then pulled down to ground with a resistance of approximately
10k. Referring to Figure 1, the synchronization threshold is 1.4 V. The oscillator blanks any synchronization pulse
that occurs when OSC is below 2.5 V. This allows units, once they discharge below 2.5 V, to continue through
the current discharge and subsequent charge cycles whether or not other units on the CLKSYN bus are still
synchronizing. This requires the frequency of all free running oscillators to be within 17% of each other to assure
synchronization.
7
相關(guān)PDF資料
PDF描述
UC2306L-50-S08-T 1.2 A SWITCHING REGULATOR, PDSO8
UC2843AQD8RG4 1 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO8
UC3827Q-1 1 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PQCC28
UC3842ADX
UC3843ADX
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
UC1827L-1 制造商:TI 制造商全稱:Texas Instruments 功能描述:Buck Current/Voltage Fed Push-Pull PWM Controllers
UC1827-X 制造商:TI 制造商全稱:Texas Instruments 功能描述:Buck Current/Voltage Fed Push-Pull PWM Controllers
UC182DW 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC
UC182DWTR 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC
UC182J 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC