參數(shù)資料
型號: SA57254-XX
廠商: NXP Semiconductors N.V.
元件分類: 基準電壓源/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安培開關穩(wěn)壓器
文件頁數(shù): 11/18頁
文件大?。?/td> 267K
代理商: SA57254-XX
Philips Semiconductors
Product data
SA57254-XX
CMOS switching regulator (PWM controlled)
2003 Nov 11
11
Period 1: power switch on-time
During this period, a simple circuit loop is formed when the power
switch is on. The input voltage source is connected directly across
the boost inductor (L
0
). A current ramp is exhibited whose slope is
described by:
IL
(on)
V
IN
L
0
Eqn. (1)
Energy is then stored within the core material of the inductor and is
described by:
E
sto
0.5L
0
I
peak
2
Eqn. (2)
This current ramp continues until the controller turns off the power
switch.
Period 2: inductor discharge period
The instant the power switch turns off, the current flowing through
the inductor forces the voltage at its output node (switched node) to
rise quickly above the input voltage (spike). This voltage is then
clamped when it exceeds the device’s output voltage and the output
rectifier becomes forward biased. The inductor empties its stored
energy in the form of a linearly decreasing current ramp whose
slope is dictated by:
I
L(off)
V
IN
V
OUT
L
0
Eqn. (3)
The stored energy is transferred to the output capacitor. This output
current continues until the magnetic core is completely emptied of its
stored energy or the power switch turns back on.
Period 3: inductor empty state
D
ISCONTINUOUS
MODE
This period as displayed in Figure 25 occurs
in the discontinuous–mode of operation of a boost converter. It is
identified by a period of “ringing” following the output period
(period 2). The inductor has been completely emptied of its stored
energy and the switched node returns to the level of the input
voltage. Ringing is seen at this node because a resonant circuit is
formed by the inductance of L
0
and any parasitic inductances and
capacitances connected to that node. This ringing has very little
energy and can easily be eliminated by a small passive snubber.
C
ONTINUOUS
MODE
If the inductor is not completely emptied of its
stored energy before the power switch turns on again, the converter
is operating in the continuous mode. A small amount of residual flux
(energy) remains in the inductor core and the current waveform
jumps to an initial value when the power switch is again turned-on.
This mode offers some advantages over the discontinuous-mode,
because the peak current seen by the power switch is lower. In low
voltage applications, the inductor can store more energy with lower
peak currents.
The continuous mode waveforms can be seen in Figure 26.
S
I
0
SPIKE
+V
OUT
+V
IN
V
IN
L
0
(V
IN
– V
OUT
)
L
0
I
peak
RESIDUAL FLUX
ENERGY BEING
TRANSFERRED
TO OUTPUT
ENERGY BEING
STORED IN
INDUCTOR
SL01465
Figure 26. Continuous mode waveforms.
相關PDF資料
PDF描述
SA57254-28GW RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
SA57254-30GW Ceramic Multilayer Capacitor; Capacitance:47pF; Capacitance Tolerance:+/- 5 %; Working Voltage, DC:100V; Dielectric Characteristic:C0G/NP0; Package/Case:0603; Series:VJ; Leaded Process Compatible:Yes; Mounting Type:Surface Mount
SA57254-33GW RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
SA57254-36GW RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
SA57254-50GW Ceramic Multilayer Capacitor; Capacitance:4.7pF; Capacitance Tolerance:+/- 0.25 pF; Working Voltage, DC:50V; Dielectric Characteristic:C0G/NP0; Package/Case:0603; Series:VJ; Leaded Process Compatible:Yes; Mounting Type:Surface Mount
相關代理商/技術參數(shù)
參數(shù)描述
SA57254-XXGW 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:CMOS switching regulator (PWM controlled)
SA572D 功能描述:音頻放大器 Dual Channel Hi Perf RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
SA572DG 功能描述:音頻放大器 Dual Channel Hi Perf Compandor Ind. Temp RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
SA572DG 制造商:ON Semiconductor 功能描述:Standard Recovery Rectifier
SA572DR2 功能描述:音頻放大器 Dual Channel Hi Perf RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel