1. Trang chủ
  2. » Kỹ Thuật - Công Nghệ

Tài liệu Power Supply Block Diagram ppt

53 403 1

Đang tải... (xem toàn văn)

Tài liệu hạn chế xem trước, để xem đầy đủ mời bạn chọn Tải xuống

THÔNG TIN TÀI LIỆU

Thông tin cơ bản

Định dạng
Số trang 53
Dung lượng 280,11 KB

Nội dung

Power Supply Block DiagramPower Supply Block Diagram H. Chan; Mohawk College 1 HalfHalf--Wave RectifierWave Rectifier 7.0V2V SP −= ⎟ ⎟ ⎞ ⎜ ⎜ ⎛ −= Pd 00833.0 1VV V ⎟ ⎠ ⎜ ⎝ FL Pdc CR V00480 FL P r CR V0048.0 V = H. Chan; Mohawk College 2 FL t FullFull--Wave RectifierWave Rectifier 7.0V707.0V sP −= ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ −= Pdc CR 00417.0 1VV V ⎟ ⎠ ⎜ ⎝ FL Pdc CR V00240 V FL P r CR V0024.0 V = t H. Chan; Mohawk College 3 FL CR t BridgeBridge--Type RectifierType Rectifier 4.1V2V sP −= ⎟ ⎟ ⎞ ⎜ ⎜ ⎛ −= Pdc 00417.0 1VV V ⎟ ⎠ ⎜ ⎝ FL Pdc CR V00240 V FL P r CR V0024.0 V = t H. Chan; Mohawk College 4 FL CR t More Equations . . . More Equations . . . Rithi ti V V + 1 736 V Rearranging the previous equations: V P = V dc + 1.736 V r The ripple voltage as a percentage of the dc voltage is: V 100% x V V ripple dc r = The diode(s) must be rated to withstand the surge current: P V where R W is the transformer winding’s W P surge R V I = W g resistance given by: FLNL W I VV R − = H. Chan; Mohawk College 5 FL I Comparison of Different Types of RectifiersComparison of Different Types of Rectifiers  Half-wave rectifier needs only a single diode but ripple is twice those of the other types. ll ifi i d  Full-wave rectifier requires a centre-tapped transformer and its output voltage is about half those of the other types.those of the other types.  Bridge-type rectifier is best overall even though it requires four diodes because the diode bridge is often available in a single package. However, if a single diode in the bridge is defective, the whole package has to be replaced H. Chan; Mohawk College 6 whole package has to be replaced. Line RegulationLine Regulation is a measure of the effectiveness of a voltage regulatoris a measure of the effectiveness of a voltage regulator to maintain the output dc voltage constant despite chan ges in the supply voltage. o V VmVregulationLine Δ =)/( gppyg i V VmVregulationLine Δ )/( i o V x V V regulationline 100 % Δ Δ = H. Chan; Mohawk College 7 oi VVΔ Load RegulationLoad Regulation i f th bilit f l t t i t iis a measure of the ability of a regulator to maintain a constant dc output despite changes in the load current. o I V AmVregulationLoad Δ Δ =)/( L I g Δ )( V 100 Δ oL o V x I V regulationload 100 % Δ Δ = H. Chan; Mohawk College 8 Other SpecificationsOther Specifications A d fi iti f lt l ti iA common definition for voltage regulation is: 100(%) x VV regulationVoltage FLNL − =() V gg FL The ability to reduce the output ripple voltage is: )( )( log20)( inr outr V V dBrejectionRipple −= )(inr Source resistance of regulator is: ΩΩ Δ Δ = mor I V R o s H. Chan; Mohawk College 9 g ΔI L Zener Diode Voltage RegulatorZener Diode Voltage Regulator I-V Characteristic Circuit I ZM H. Chan; Mohawk College 10 ZM [...]... H Chan; Mohawk College 30 78XX Regulator with Pass Transistor 0 7 R1 = I max 0 7 R2 = I R2 H Chan; Mohawk College Q1 starts to conduct when VR2 = 0.7 V R2 is typically chosen so that max IR2 is 0.1 A Power dissipation of Q1 is i P = (Vi - Vo)IL Q2 is for current limiting protection It conducts when VR1 = 0.7 V Q2 must be able to pass ; max 1 A; but note that max VCE2 is only 1.4 V 31 78XX Floating... a variable regulator by replacing R2 with a pot However, However there are several disadvantages: Minimum output voltage is Vreg instead of 0 V IQ is relatively large and varies from chip to chip chip Power dissipation in R2 can in some cases be quite large resulting in bulky and expensive equipment A variety of 3-terminal variable regulators are available, e.g LM317 (for +ve output) or LM 337 (for . Power Supply Block DiagramPower Supply Block Diagram H. Chan; Mohawk College 1 HalfHalf--Wave RectifierWave. regulator to maintain the output dc voltage constant despite chan ges in the supply voltage. o V VmVregulationLine Δ =)/( gppyg i V VmVregulationLine Δ )/(

Ngày đăng: 13/12/2013, 23:15

TỪ KHÓA LIÊN QUAN

w