参数资料
| 型号： | ISL6567CRZ |
| 厂商： | Intersil |
| 文件页数： | 10/25页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 24-QFN |
| 标准包装： | 75 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1.5MHz |
| 占空比： | 66% |
| 电源电压： | 4.9 V ~ 5.5 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： | 0°C ~ 70°C |
| 封装/外壳： | 24-VFQFN 裸露焊盘 |
| 包装： | 管件 |
| 产品目录页面： | 1243 (CN2011-ZH PDF) |
ISL6567
( V IN – N ? V OUT ) ? V OUT
L ? f S ? V
presents additional technical challenges, the multi-phase
approach offers advantages with improved response time,
superior ripple cancellation, and thermal distribution.
INTERLEAVING
The switching of each channel in a ISL6567-based converter is
timed to be symmetrically out-of-phase with the other channel.
As a result, the two-phase converter has a combined ripple
frequency twice the frequency of one of its phases. In addition,
the peak-to-peak amplitude of the combined inductor currents
is proportionately reduced. Increased ripple frequency and
lower ripple amplitude generally translate to lower per-channel
inductance and/or lower total output capacitance for any given
set of performance specification.
I PP = -------------------------------------------------------------
IN
C IN CURRENT
Q1 D-S CURRENT
(EQ. 4)
Q3 D-S CURRENT
I L1 + I L2
FIGURE 4. INPUT CAPACITOR CURRENT AND INDIVIDUAL
( V IN – V OUT ) ? V OUT (EQ. 3)
L ? f S ? V
I L2
PWM2
I L1
PWM1
FIGURE 3. PWM AND INDUCTOR-CURRENT WAVEFORMS FOR
2-PHASE CONVERTER
Figure 3 illustrates the additive effect on output ripple
frequency. The two channel currents (I L1 and I L2 ), combine to
form the AC ripple current and the DC load current. The ripple
component has two times the ripple frequency of each
individual channel current.
To understand the reduction of ripple current amplitude in the
multi-phase circuit, examine the equation representing an
individual channel’s peak-to-peak inductor current.
I L , PP = ---------------------------------------------------
IN
V IN and V OUT are the input and output voltages, respectively, L
is the single-channel inductor value, and f S is the switching
frequency.
The output capacitors conduct the ripple component of the
inductor current. In the case of multi-phase converters, the
capacitor current is the sum of the ripple currents from each of
the individual channels. Peak-to-peak ripple current decreases
by an amount proportional to the number of channels.
Output-voltage ripple is a function of capacitance, capacitor
equivalent series resistance (ESR), and inductor ripple current.
Reducing the inductor ripple current allows the designer to use
fewer or less costly output capacitors (should output
high-frequency ripple be an important design parameter).
10
CHANNEL CURRENTS IN A 2-PHASE CONVERTER
Another benefit of interleaving is the reduction of input ripple
current. Input capacitance is determined in a large part by the
maximum input ripple current. Multi-phase topologies can
improve overall system cost and size by lowering input ripple
current and allowing the designer to reduce the cost of input
capacitance. The example in Figure 4 illustrates input currents
from a two-phase converter combining to reduce the total
input ripple current.
Figure 28, part of the section entitled “Input Capacitor
Selection” on page 24 , can be used to determine the input
capacitor RMS current based on load current and duty cycle.
The figure is provided as an aid in determining the optimal
input capacitor solution.
PWM OPERATION
One switching cycle for the ISL6567 is defined as the time
between consecutive PWM pulse terminations (turn-off of the
upper MOSFET on a channel). Each cycle begins when a
switching clock signal commands the upper MOSFET to go off.
The other channel’s upper MOSFET conduction is terminated
1/2 of a cycle later.
Once a channel’s upper MOSFET is turned off, the lower
MOSFET remains on for a minimum of 1/3 cycle. This forced
off time is required to assure an accurate current sample.
Following the 1/3-cycle forced off time, the controller enables
the upper MOSFET output. Once enabled, the upper MOSFET
output transitions high when the sawtooth signal crosses the
adjusted error-amplifier output signal, as illustrated in
Figure 2. Just prior to the upper drive turning the MOSFET on,
the lower MOSFET drive turns the freewheeling element off.
The upper MOSFET is kept on until the clock signals the
beginning of the next switching cycle and the PWM pulse is
terminated.
CURRENT SENSING
ISL6567 senses current by sampling the voltage across the
lower MOSFET during its conduction interval. MOSFET r DS(ON)
FN9243.4
August 9, 2011
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| ISL6567CRZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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) |
| ISL6567IRZ | 功能描述:IC REG CTRLR BUCK PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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) |
| ISL6567IRZS2698 | 功能描述:IC REG CTRLR BUCK PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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) |
| ISL6567IRZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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) |
| ISL6567IRZ-TS2698 | 功能描述:IC REG CTRLR BUCK PWM VM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 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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