參數(shù)資料
型號(hào): ISL6174IRZ
廠商: Intersil
文件頁(yè)數(shù): 9/16頁(yè)
文件大小: 346K
描述: IC CIRC BREAKER DUAL LV 28-QFN
標(biāo)準(zhǔn)包裝: 60
類型: 熱交換控制器
應(yīng)用: 通用
內(nèi)部開(kāi)關(guān): 無(wú)
電源電壓: 2.25 V ~ 3.63 V
工作溫度: -40°C ~ 85°C
安裝類型: 表面貼裝
封裝/外殼: 28-VFQFN 裸露焊盤(pán)
供應(yīng)商設(shè)備封裝: 28-QFN 裸露焊盤(pán)(5x5)
包裝: 管件
9
FN6830.0
December 19, 2008
Detailed Description of Operation
ISL6174 targets dual voltage hot-swap applications with a
bias of 2.1V to 3.6VDC and the voltages being controlled
down to 0.7VDC. The ICs main functions are to control start-
up inrush current and provide circuit breaker protection of
the sourcing supplies from OC loads. This is achieved by
enhancing an external MOSFET in a controlled manner. In
order to fully enhance the MOSFET, the IC must provide
adequate gate to source voltage, which is typically 5V or
greater. Hence, the final steady-state voltage on Gate (GT)
pin must be a minimum of 5V above the load voltage. Two
internal charge-pumps allow this to happen.
Controlled Soft-Start
The output voltages are monitored through the Vo pins and
slew up at a rate determined by the capacitors on the
Soft-start (SS) pin, as illustrated in Figure 15. 24礎(chǔ) of gate
charge current is available. The soft-start amplifier controls
the output voltage by robbing some of the gate charge
current thus slowing down the MOSFET enhancement.
When the load voltage reaches its set level, as sensed by its
respective UV pin through an external resistor divider, the
Power Good (PG
) output goes active.
Current Monitoring and Circuit Breaker Protection
The IC monitors the load current (Io) by sensing the
voltage-drop across the low value current sense resistor
(R
SNS
), which is connected in series with the MOSFET (as
shown in the Block Diagram on page 2), through Sense
(SNS) and voltage set (VS) pins. The latter is through a
resistor, R
SET
, as shown. Two levels of overcurrent
detection are available to protect against all possible fault
scenarios. These levels are:
"  Timed Circuit Breaker (CB)
"  Way Overcurrent Circuit Breaker (WOC)
Each of these modes is described in detail as follows:
TIMED CIRCUIT BREAKER (CB) MODE
When the load current reaches the Circuit Breaker threshold
(I
CB
) the ISL6174 enters the timed Circuit Breaker Mode.
When the circuit enters this mode, the OC comparator which
directly looks at the voltage drop across R
SNS
 detects it and
starts the CB delay timer. TCB begins to charge whatever
capacitance is on that pin from an internal 10礎(chǔ) current
source. The amount of time it takes for this capacitance to
charge to ~1.18V (V
CT_Vth
) sets up the Circuit Breaker delay.
Upon expiration of the CB delay (t
CB
), the MOSFET gate is
pulled down quickly.
If during and prior to t
CB
 expiring the load current falls below
I
CB
 then in that case, the Circuit Breaker mode is no longer
active and the IC discharges the C
TCB
 cap.
The Circuit Breaker threshold (I
CB
) is set by sinking a
reference current, I
SET
, through R
SET
 by selecting an
appropriate resistor between OCREF and GND, which sets
I
REF
. The relationship between I
REF
 and I
SET
 is I
REF
 =
4*I
SET
, where I
REF
 = Vocref/Rocref = 1.178/Rocref. I
REF
 
would typically be set at 80礎(chǔ). This I
SET
 * R
SET
voltage is
then compared to the voltage across a load current series
sense low ohmic resistor.
Selecting appropriate values for R
SET
 and R
SNS
 such that
when I
O
 = I
CR
,
WAY OVERCURRENT CIRCUIT BREAKER (WOC) MODE
This mode is designed to handle very fast, very low
impedance shorts on the load side, which can result in very
high di/dt transients on the input current. The WOC circuit
breaker level is typically 200% of the Circuit Breaker limit. In
this mode the comparator, which directly looks at the voltage
drop across R
SNS
 and once the WOC level is exceeded the
IC pulls the gate very quickly to GND, the SSx capacitor is
discharged, FLT
 is asserted and a new SS sequence is
allowed to begin after ENx
 recycle.
Q
SS1
10V
CPVDD
SOFT-
START
AMPLIFIER
24礎(chǔ)
10礎(chǔ)
+
42礎(chǔ)
VO
0
0
VIN
CPVDD
VIN
+
-
-
FIGURE 15. SOFT-START OPERATION
(EQ. 1)
Io*R
SNS
 = I
SET
*R
SET
ISL6174
相關(guān)PDF資料
PDF描述
ISL61861DCBZ IC USB PWR CTRLR 3A 8SOIC
ISL6402IR IC REG TRPL BCK/LINEAR 28-QFN
ISL6413IRZ-TK IC REG TRPL BCK/LINEAR 24-QFN
ISL6432CB-T IC REG QD BCK/LINEAR 16-SOIC
ISL6521CBZS2698 IC REG QD BCK/LINEAR 16-SOIC
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ISL6174IRZ-T 功能描述:IC CIRC BREAKER DUAL LV 28-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:100 系列:- 類型:熱插拔開(kāi)關(guān) 應(yīng)用:通用 內(nèi)部開(kāi)關(guān):是 電流限制:可調(diào) 電源電壓:9 V ~ 13.2 V 工作溫度:-40°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:10-TDFN-EP(3x3) 包裝:管件
ISL617XEVAL1Z 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Dual Low Voltage Circuit Breaker
ISL6185 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Dual USB Port Power Supply Controller
ISL6185_11 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Dual USB Port Power Supply Controller 2.5V to 5V Operating Range
ISL61851ACBZ 功能描述:熱插拔功率分布 DL USB HOTSWAP W/INT FET-EN HI 8LD RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube