参数资料
| 型号： | ISL62870HRUZ-T |
| 厂商： | Intersil |
| 文件页数： | 7/16页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM 16-TQFN |
| 标准包装： | 3,000 |
| 系列： | Robust Ripple Regulator™ (R³) |
| PWM 型： | 控制器 |
| 输出数： | 1 |
| 频率 - 最大： | 330kHz |
| 占空比： | 100% |
| 电源电压： | 3.3 V ~ 25 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -10°C ~ 100°C |
| 封装/外壳： | 16-UFQFN |
| 包装： | 带卷 (TR) |
ISL62870
V OUT
R FB
FB
?
V COMP
Fault Protection
Overcurrent
+
EA
The overcurrent protection (OCP) setpoint is programmed
SREF
+
V SET
?
V REF
with resistor R OCSET , which is connected across the
OCSET and PHASE pins. Resistor R O is connected
between the VO pin and the actual output voltage of the
converter. During normal operation, the VO pin is a high
impedance path, therefore there is no voltage drop across
R O . The value of resistor R O should always match the value
of resistor R OCSET .
L
FIGURE 4. ISL62870 VOLTAGE PROGRAMMING CIRCUIT
PHASE
+
DCR
R OCSET
V DCR
C SEN
I L
_
V O
C O
Soft-Start Delay
10?μ
OCSET
+ V ROCSET
_
V DCR = I L ? DCR
V SREF ? C SOFT
t SS = -------------------------------------------
C SOFT = -----------------------
R OCSET = ----------------------------
Circuit Description
When the voltage on the VCC pin has ramped above the
rising power-on reset voltage V VCC_THR , and the voltage on
the EN pin has increased above the rising enable threshold
voltage V ENTHR , the SREF pin releases its discharge clamp,
and enables the reference amplifier V SET . The soft-start
current I SS is limited to 20μA and is sourced out of the SREF
pin and charges capacitor C SOFT until V SREF equals V REF .
The regulator controls the PWM such that the voltage on the
FB pin tracks the rising voltage on the SREF pin. The
elapsed time from when the EN pin is asserted to when
V SREF has charged C SOFT to V REF is called the soft-start
delay t SS which is given by Equation 3:
(EQ. 3)
I SS
Where:
- I SS is the soft-start current source at the 20μA limit
- V SREF is the buffered V REF reference voltage
The end of soft-start is detected by I SS tapering off when
capacitor C SOFT charges to V REF . The internal SSOK flag is
set, the PGOOD pin goes high, and diode emulation mode
(DEM) is enabled.
Component Selection For C SOFT Capacitor
Choosing the C SOFT capacitor to meet the requirements of a
particular soft-start delay t SS is calculated using Equation 4,
which is written as follows:
t SS ? I SS
(EQ. 4)
V SREF
Where:
- t SS is the soft-start delay
- I SS is the 20μA soft-start current source at the 20μA
limit
- V SREF is the buffered V REF reference voltage
7
R O
VO
FIGURE 5. OVERCURRENT PROGRAMMING CIRCUIT
Figure 5 shows the overcurrent set circuit. The inductor
consists of inductance L and the DC resistance DCR. The
inductor DC current I L creates a voltage drop across DCR,
which is given by Equation 5:
(EQ. 5)
The I OCSET current source sinks 10μA into the OCSET pin,
creating a DC voltage drop across the resistor R OCSET,
which is given by Equation 6:
V ROCSET = 10 μ A ? R OCSET (EQ. 6)
The DC voltage difference between the OCSET pin and the
VO pin, which is given by Equation 7:
V OCSET – V VO = V DCR – V ROCSET = I L ? DCR – I OCSET ? R OCSET
(EQ. 7)
The IC monitors the voltage of the OCSET pin and the VO
pin. When the voltage of the OCSET pin is higher than the
voltage of the VO pin for more than 10μs, an OCP fault
latches the converter off.
Component Selection For R OCSET and C SEN
The value of R OCSET is calculated with Equation 8 which is
written as follows:
I OC ? DCR
(EQ. 8)
I OCSET
Where:
- R OCSET ( Ω ) is the resistor used to program the
overcurrent setpoint
- I OC is the output DC load current that will activate the
OCP fault detection circuit
- DCR is the inductor DC resistance
FN6708.0
August 14, 2008
相关PDF资料 |
PDF描述 |
|---|---|
| ISL62872HRUZ-T | IC REG CTRLR BUCK PWM 20-TQFN |
| ISL62873HRUZ-T | IC REG CTRLR BUCK PWM 16UTQFN |
| ISL62875HRUZ-T | IC REG CTRLR BUCK PWM 20UTQFN |
| ISL62881CIRTZ | IC REG PWM SGL PHASE 28TQFN |
| ISL62881HRTZ | IC REG PWM SGL PHASE 28TQFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL62871 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:PWM DC/DC Controller With VID Inputs For Portable GPU Core-Voltage Regulator |
| ISL62871HRUZ | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:PWM DC/DC Controller With VID Inputs For Portable GPU Core-Voltage Regulator |
| ISL62871HRUZ-T | 功能描述:IC REG CTRLR BUCK PWM 16-TQFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:Robust Ripple Regulator™ (R³) 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL62872HRUZ | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:PWM DC/DC Controller With VID Inputs For Portable GPU Core-Voltage Regulator |
| ISL62872HRUZ-T | 功能描述:IC REG CTRLR BUCK PWM 20-TQFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:Robust Ripple Regulator™ (R³) 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
发布紧急采购，3分钟左右您将得到回复。