- 您現(xiàn)在的位置：買(mǎi)賣(mài)IC網(wǎng) > PDF目錄385855 > SP6121EB Demo Board Manual PDF資料下載
參數(shù)資料
| 型號(hào)： | SP6121EB |
| 英文描述： | Demo Board Manual |
| 中文描述： | 演示板手冊(cè) |
| 文件頁(yè)數(shù)： | 13/16頁(yè) |
| 文件大?。?/td> | 358K |
| 代理商： | SP6121EB |
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)第12頁(yè)當(dāng)前第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)
Date: 5/25/04
SP6121 Low Voltage, Synchronous Step Down PWM Controller Copyright 2004 Sipex Corporation
13
Figure 7(A) A voltage divider connected to the V
FB
pin programs the output voltage. (B) A simple circuit using one
external voltage reference programs the output voltages less than 1.25V.
A
B
V
REF
V
FB
V
FB
V
OUT
< 1.25V
V
OUT
> 1.25V
SP6121
SP6121
R1
R2
R1
R2
R3
C
IN
I
SET
V
IN
PDRV
SP6121
NDRV
I
SENSE
V
OUT
L1
C
OUT
RSET
Q1
Q2
+
-
+
-
30
μ
A
Figure 6. Current Limit Setting
The value of R
SET
can be properly chosen based on
the desired current limit point I
MAX
and the internal
30
μ
A pull down current available on the I
SET
pin
according to the following expression:
R
SET
= I
MAX
R
DS(ON)
- 160mV
I
SET
where,
I
SET
= 30
μ
A (typ) sink current from the I
SET
pin.
Kelvin-Sense connections should be made di-
rectly at the drain and source of Q1.
The R
DS(ON)
sensing scheme implemented in the
SP6121 provides two additional features that
enhance the performance of the overcurrent
function. First, an internal sample and hold filter
connected after the main current-sense com-
parator, prevents that noise spikes or very short
and mild overload conditions, that could occur
during a load transient, spuriously activate the
current limit circuitry. This typically eliminates
the need of using any external filtering that would
be otherwise required. Additionally, since the
R
DS(ON)
has a positive temperature coefficient,
both the 30
μ
A sink current present at the I
SET
pin
and the 160mV built-in current limit threshold
have been designed with a positive temperature
coefficient of about 0.33%/C to provide first order
correction for current limit versus temperature.
This compensation relies on the high amount of
thermal coupling that typically exists between the
high side switch Q1 and the SP6121 due to the
compact size of the power supply. With this first
order compensation, the current limit trip point
does not need to be set to an increased level at room
temperature to guarantee a desired output current
level at higher temperatures.
Output Voltage Program
As shown in Figure 7(A), the voltage divider
connecting to the V
FB
pin programs the output
voltage according to
V
OUT
= 1.25
(
1 + R1
)
R2
where 1.25V is the internal reference voltage.
Select R2 in the range of 10k to 100k, and R1 can
be calculated using
R2(V
OUT
- 1.25)
R1 =
1.25
For output voltage less than 1.25V, a simple
circuit shown in Figure 7(B) can be used in
which V
REF
is an external voltage reference
greater than 1.25V. For simplicity, use the same
resistor value for R1 and R2, then R3 is deter-
mined as follows,
(V
REF
- 1.25)R1
2.5V - V
OUT
R3 =
APPLICATIONS INFORMATION: Continued
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SP6132H | High Voltage, 300KHz Synchronous PWM Controller |
| SP6132HEU | High Voltage, 300KHz Synchronous PWM Controller |
| SP6134 | Dual Supply Synchronous Buck Controller |
| SP6134CU | Dual Supply Synchronous Buck Controller |
| SP6134EU | Dual Supply Synchronous Buck Controller |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SP6122 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Low Voltage, Micro 8, PFET, Buck Controller Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters |
| SP6122_04 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Low Voltage, Micro 8, PFET, Buck Controller Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters |
| SP6122ACU | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| SP6122ACU/TR | 制造商:Exar Corporation 功能描述: |
| SP6122ACU-1.5 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Low Voltage, Micro 8, PFET, Buck Controller Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。