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参数资料
| 型号： | 750106 |
| 厂商： | Wurth Electronics Inc |
| 文件页数： | 8/24页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR LT3575 |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，隔离 |
| 功率 - 输出： | 10W |
| 输出电压： | 5V |
| 电流 - 输出： | 2A（最小值） |
| 输入电压： | 10 ~ 28 VDC |
| 稳压器拓扑结构： | 回扫 |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | LT3575 |
| 相关产品： | LT3575IFE#TRPBF-ND - IC REG FLYBACK ISO ADJ 16TSSOP LT3575IFE#PBF-ND - IC REG FLYBACK ISO ADJ 16TSSOP LT3575EFE#TRPBF-ND - IC REG FLYBACK ISO ADJ 16TSSOP LT3575EFE#PBF-ND - IC REG FLYBACK ISO ADJ 16TSSOP |
| 其它名称： | 732-3306 |
LT3575
APPLICATIONS INFORMATION
? R FB ? ? 1 ?
? ? V F SEC ( ES R )
V OUT BG ?
? ? ? α N
ERROR AMPLIFIER—PSEUDO DC THEORY
In the Block Diagram, the R REF (R4) and R FB (R3) resistors
can be found. They are external resistors used to program
the output voltage. The LT3575 operates much the same way
as traditional current mode switchers, the major difference
being a different type of error ampli?er which derives its
feedback information from the ?yback pulse.
Operation is as follows: when the output switch, Q1,
turns off, its collector voltage rises above the V IN rail. The
amplitude of this ?yback pulse, i.e., the difference between
it and V IN , is given as:
V FLBK = (V OUT + V F + I SEC ? ESR) ? N PS
V F = D1 forward voltage
I SEC = Transformer secondary current
ESR = Total impedance of secondary circuit
N PS = Transformer effective primary-to-secondary
turns ratio
The ?yback voltage is then converted to a current by
In combination with the previous V FLBK expression yields
an expression for V OUT , in terms of the internal reference,
programming resistors, transformer turns ratio and diode
forward voltage drop:
= V ? I
? R REF ? PS ?
Additionally, it includes the effect of nonzero secondary
output impedance (ESR). This term can be assumed to
be zero in boundary control mode. More details will be
discussed in the next section.
Temperature Compensation
The ?rst term in the V OUT equation does not have a tem-
perature dependence, but the diode forward drop has a
signi?cant negative temperature coef?cient. To compen-
sate for this, a positive temperature coef?cient current
source is connected to the R REF pin. The current is set by
a resistor to ground connected to the TC pin. To cancel the
temperature coef?cient, the following equation is used:
δ V F R FB
δ T
? R FB
δ V TC
δ V TC R FB
δ T
the action of R FB and Q2. Nearly all of this current ?ows
through resistor R REF to form a ground-referred voltage.
This voltage is fed into the ?yback error ampli?er. The
?yback error ampli?er samples this output voltage
information when the secondary side winding current is
=?
R TC
R TC =
N PS
?
1
? ?
N PS
1
δ V F / δ T
δ T
or ,
? ≈
N PS
zero. The error ampli?er uses a bandgap voltage, 1.23V,
as the reference voltage.
The relatively high gain in the overall loop will then cause
the voltage at the R REF resistor to be nearly equal to the
bandgap reference voltage V BG . The relationship between
V FLBK and V BG may then be expressed as:
( δ V F / δ T ) = Diode’s forward voltage temperature
coef?cient
( δ V TC / δ T) = 2mV
V TC = 0.55V
The resistor value given by this equation should also be
α ? FLBK ? =
? V ?
? R FB ?
V BG
R REF
or ,
veri?ed experimentally, and adjusted if necessary to achieve
optimal regulation overtemperature.
= V BG ?
? R FB ? ? 1 ?
? R REF ? ? ? ? α ? ?
? R FB ? ? 1 ?
? ? V F
V OUT BG ?
? ? ? N
? R REF ? PS α ?
? ? TC ? ? – I SEC ( ESR )
V FLBK
α = Ratio of Q1 I C to I E , typically ≈ 0.986
V BG = Internal bandgap reference
The revised output voltage is as follows:
= V
? V ? R FB
? R TC ? N PS α
3575f
8
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 750-106 | 制造商:GLENAIR 制造商全称:Glenair, Inc. 功能描述:Pre-Terminated Assemblies |
| 750107 | 功能描述:BOARD EVAL FOR LT3748 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 标准包装:1 系列:- 主要目的:DC/DC，步降 输出及类型:1，非隔离 功率 - 输出:- 输出电压:3.3V 电流 - 输出:3A 输入电压:4.5 V ~ 28 V 稳压器拓扑结构:降压 频率 - 开关:250kHz 板类型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名称:497-12113STEVAL-ISA094V1-ND |
| 7501078 | 制造商:ARK-LES CONNECTORS 功能描述:.240 SQUARED RING TERMINAL 16-14 AWG 6 STUD SIZE |
| 750108 | 功能描述:BOARD EVAL FOR LT3748 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 标准包装:1 系列:- 主要目的:DC/DC，步降 输出及类型:1，非隔离 功率 - 输出:- 输出电压:3.3V 电流 - 输出:3A 输入电压:4.5 V ~ 28 V 稳压器拓扑结构:降压 频率 - 开关:250kHz 板类型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名称:497-12113STEVAL-ISA094V1-ND |
| 750109 | 制造商:Pilz International 功能描述:CONTACT MODULE 3NO/1NC 24V 制造商:PILZ 功能描述:CONTACT MODULE, 3NO/1NC, 24V, 30OHM 制造商:PILZ 功能描述:CONTACT MODULE, 3NO/1NC, 24V, 30OHM; Coil Voltage VDC Nom:24V; Contact Current Max:6A; Contact Voltage AC Nom:240V; Contact Voltage DC Max:24V; Coil Resistance:30ohm; Contact Configuration:3PST-NO, SPST-NC; Average Power ;RoHS Compliant: Yes |
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