参数资料
| 型号： | ISL95870BHRZ |
| 厂商： | Intersil |
| 文件页数： | 18/28页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR PWM 1PHASE GPU 20QFN |
| 标准包装： | 75 |
| 应用： | 控制器，GPU 内核电源 |
| 输入电压： | 3.3 V ~ 25 V |
| 输出数： | 1 |
| 输出电压： | 0.5 V ~ 5 V |
| 工作温度： | -10°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-VFQFN 裸露焊盘 |
| 供应商设备封装： | 20-QFN（3x4） |
| 包装： | 管件 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页当前第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页
ISL95870, ISL95870A, ISL95870B
The ISL95870B V SET3 setpoint is written as Equation 23:
V SET3 = V REF ? ? 1 + -------------------------------------------- ?
? R SET1 + R SET2 ?
? R SET3 + R SET4 ?
(EQ. 23)
VOUT
RFB
FB
-
VCOMP
The ISL95870B V SET4 setpoint is written as Equation 24:
+
EA
V SET4 = V REF ? ? 1 + --------------------------------------------------------------------- ?
? R SET1 + R SET2 + R SET3 ?
? R SET4 ?
(EQ. 24)
+
VREF
0.5V
V SET
The V SET1 is fixed at 0.5V because it corresponds to the closure
of internal switch SW0 that configures the V SET amplifier as a
unity-gain voltage follower for the 0.5V voltage reference V REF .
The setpoint reference voltages use the naming convention
V SET(x) where (x) is the first, second, third, or fourth setpoint
reference voltage where:
- V SET1 < V SET2 < V SET3 < V SET4 thus,
SREF
SET0
SW0
SW1
-
- V OUT1 < V OUT2 < V OUT3 < V OUT4
V REF ? V SET2
For given four user selected reference voltages V SETx , the
programmed resistors R SET1 , R SET2 , R SET3 and R SET4 are
designed in the following way. First, assign an initial value to R SET4
of approximately 100k Ω then calculate R SET1, R SET2 and R SET3
using Equations 25, 26, and 27 respectively.
R SET4 ? V SET4 ? ( V SET2 – V REF )
(EQ. 25)
R SET1 = -------------------------------------------------------------------------------------------
SET1
SET2
SW2
SW3
V SET2 ? V SET3
R SET4 ? V SET4 ? ( V SET3 – V SET2 )
R SET2 = ----------------------------------------------------------------------------------------------
(EQ. 26)
FIGURE 11. ISL95870B VOLTAGE PROGRAMMING CIRCUIT
R SET4 ? ( V SET4 – V SET3 )
R SET3 = -----------------------------------------------------------------------
R SET1 + R SET2 + R SET3 + R SET4 ? 300k Ω
R FB + R OFS
V OUT = V SREF ? ---------------------------------- = V SREF ? k
R
V OUTx = V SETx ? k
(EQ. 27)
V SET3
The sum of all the programming resistors should be
approximately 300k Ω, as shown in Equation 28, otherwise
adjust the value of R SET4 and repeat the calculations.
(EQ. 28)
If the output voltage is in the range of 0.5V to 1.5V, the external
resistor-divider is not necessary. The output voltage is equal to
one of the reference voltages depending on the status of VID1
and VID0. The external resistor divider consisting of R FB and
R OFS allows the user to program the output voltage in the range
of 1.5V to 5V. The relation between the output voltage and the
reference is given in Equation 29:
(EQ. 29)
OFS
In this case, the four output voltages are equal to each of the
corresponding reference voltages multiplying the factor k.
(EQ. 30)
18
High Output Voltage Programming
The ISL95870 has a fixed 0.5V reference voltage (V SREF ). For
high output voltage application, the resistor divider consisting of
R FB and R OFS requires large ratio (R FB :R OFS = 9:1 for 5V
output). The FB pin with large ratio resistor divider is noise
sensitive and the PCB layout should be carefully routed. It is
recommended to use small value resistor divider such as
R FB =1k Ω.
In general the ISL95870A and ISL95870B have much better
jitter performance than the ISL95870 when the output voltage is
in the range of 3.3V to 5V, particularly in DCM. This is because
V SREF voltage can be set to 1.5V and a smaller ratio resistor
divider can be used. This makes the singal to noise ratio at FB pin
much better. So for 3.3V to 5V output, the ISL95870A and
ISL95870B are recommended with V SREF set to 1.5V.
R4 Modulator
The R 4 modulator is an evolutionary step in R 3 technology. Like
R 3 , the R 4 modulator allows variable frequency in response to
load transients and maintains the benefits of current-mode
hysteretic controllers. However, in addition, the R 4 modulator
reduces regulator output impedance and uses accurate
referencing to eliminate the need for a high-gain voltage
amplifier in the compensation loop. The result is a topology that
can be tuned to voltage-mode hysteretic transient speed while
maintaining a linear control model and removes the need for any
compensation. This greatly simplifies the regulator design for
customers and reduces external component cost.
FN6899.1
December 2, 2013
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL95870BHRZ-T | 功能描述:电流型 PWM 控制器 0/2 BIT PWM GPU CONTLR FOR NOTEBOOK RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL95870BHRZ-TS2490 | 制造商:Intersil Corporation 功能描述:IBM, ISL95870BHRZ-T W/CONTAINER LABELING - Tape and Reel |
| ISL95870BHRZ-TS2568 | 制造商:Intersil Corporation 功能描述:INTEL, ISL95870BHRTZ-T W/BARCODE LABELS, 12 MONTH D/C RESTRI - Tape and Reel |
| ISL95870BIRZ | 功能描述:电流型 PWM 控制器 0/2 BIT PWM GPU CONTLR FOR NOTEBOOK RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL95870BIRZ-T | 功能描述:电流型 PWM 控制器 0/2 BIT PWM GPU CONTLR FOR NOTEBOOK RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
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