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| 型号： | ISL6228EVAL3Z |
| 厂商： | Intersil |
| 文件页数： | 8/16页 |
| 文件大小： | 0K |
| 描述： | EVALUATION BOARD FOR ISL6228 |
| 标准包装： | 1 |
| 系列： | Robust Ripple Regulator™ (R³) |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 2，非隔离 |
| 输出电压： | 1.5V 或 1.8V，1.8V |
| 电流 - 输出： | 8A，8A |
| 输入电压： | 3.3 ~ 25 V |
| 稳压器拓扑结构： | 降压 |
| 频率 - 开关： | 270kHz，300kHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | ISL6228 |
ISL6228
current through C R is provided by a transconductance
amplifier g m that measures the VIN and VO pin voltages.
The positive slope of V R can be written as Equation 1:
Soft-Start Delay t SS begins and the output voltage begins to
rise. The FB pin ramps to 0.6V in approximately 1.5ms and
the PGOOD pin goes to high impedance approximately
V RPOS = ( g m ) ? ( V IN – V OUT ) ? C R
(EQ. 1)
1.25ms after the FB pin voltage reaches 0.6V.
The negative slope of V R can be written as Equation 2:
V RNEG = g m ? V OUT ? C R
(EQ. 2)
1.5ms
Vo
VCC and PVCC
Where g m is the gain of the transconductance amplifier.
A window voltage V W is referenced with respect to the error
amplifier output voltage V COMP , creating an envelope into
which the ripple voltage V R is compared. The amplitude of
V W is set by a resistor connected across the FSET and GND
pins. The V R, V COMP, and V W signals feed into a window
comparator in which V COMP is the lower threshold voltage
and V W is the higher threshold voltage. Figure 2 shows
PWM pulses being generated as V R traverses the V W and
V COMP thresholds. The PWM switching frequency is
proportional to the slew rates of the positive and negative
slopes of V R; it is inversely proportional to the voltage
between V W and V COMP.
EN
FB
PGOOD
1.25ms
FIGURE 3. SOFT-START SEQUENCE
The PGOOD pin indicates when the converter is capable of
supplying regulated voltage. The PGOOD pin is an
undefined impedance if V CC has not reached the rising POR
threshold V CCR , or if V CC is below the falling POR threshold
V CCF . The ISL6228 features a unique fault-identification
capability that can drastically reduce trouble-shooting time
and effort. The pull-down resistance of the PGOOD pin
Ripple Capacitor Voltage CR
Window Voltage VW
corresponds to the fault status of the controller. The PGOOD
pull-down resistance is 95 Ω during soft-start or if an UVP
occurs, 30 Ω for an OCP, or 60 Ω for OVP.
TABLE 1. PGOOD PULL-DOWN RESISTANCE
CONDITION
PGOOD RESISTANCE
Error Amplifier Voltage VCOMP
PWM
VCC Below POR
Soft-start or Undervoltage
Overvoltage
Overcurrent
Undefined
90 Ω
60 Ω
30 Ω
MOSFET Gate-Drive Outputs LGATE and UGATE
FIGURE 2. MODULATOR WAVEFORMS DURING LOAD
TRANSIENT
Power-On Reset
The ISL6228 is disabled until the voltage at the VCC pin has
increased above the rising power-on reset (POR) V CCR
threshold voltage. The controller will be disabled when the
voltage at the VCC pin decreases below the falling POR
V CCF threshold voltage.
EN, Soft-Start and PGOOD
The ISL6228 uses a digital soft-start circuit to ramp the
output voltage of the converter to the programmed regulation
setpoint at a predictable slew rate. The slew rate of the
soft-start sequence has been selected to limit the in-rush
current through the output capacitors as they charge to the
desired regulation voltage. When the EN pin is pulled above
the rising EN threshold voltage V ENTHR , the PGOOD
8
The ISL6228 has internal gate-drivers for the high-side and
low-side N-Channel MOSFETs. The low-side gate-drivers
are optimized for low duty-cycle applications where the low-
side MOSFET conduction losses are dominant, requiring a
low r DS(ON) MOSFET. The LGATE pull-down resistance is
small in order to clamp the gate of the MOSFET below the
V GS(th) at turnoff. The current transient through the gate at
turn-off can be considerable because the gate charge of a
low r DS(ON) MOSFET can be large. Adaptive shoot-through
protection prevents a gate-driver output from turning on until
the opposite gate-driver output has fallen below
approximately 1V. The dead-time shown in Figure 4 is
extended by the additional period that the falling gate voltage
stays above the 1V threshold. The typical dead-time is 21ns.
The high-side gate-driver output voltage is measured across
the UGATE and PHASE pins while the low-side gate-driver
output voltage is measured across the LGATE and PGND
FN9095.2
May 7, 2008
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| ISL6228HIEVAL3Z | 功能描述:EVALUATION BOARD FOR ISL6228HI RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:Robust Ripple Regulator™ (R³) 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ISL6228HRTZ | 功能描述:IC REG CTRLR BUCK PWM 28-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) |
| ISL6228HRTZ-T | 功能描述:电压模式 PWM 控制器 ISL6228 NOTEBOOK DL CNTRLR 4X4 TQFN T RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| ISL6228IRTZ | 功能描述:IC REG CTRLR BUCK PWM 28-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) |
| ISL6228IRTZ-T | 功能描述:IC REG CTRLR BUCK PWM 28-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) |
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