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参数资料
型号： MAX1544ETL+
厂商： Maxim Integrated Products
文件页数： 26/42页
文件大小： 0K
描述： IC QUICK-PWM DUAL-PHASE 40-TQFN
产品培训模块： Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装： 50
系列： Quick-PWM™
应用： 控制器，AMD Hammer
输入电压： 2 V ~ 28 V
输出数： 1
输出电压： 0.68 V ~ 1.55 V
工作温度： -40°C ~ 100°C
安装类型： 表面贴装
封装/外壳： 40-WFQFN 裸露焊盘
供应商设备封装： 40-TQFN-EP（6x6）
包装： 管件
Dual-Phase, Quick-PWM Controller for
AMD Hammer CPU Core Power Supplies
The one-shot for the secondary phase varies the on-time
in response to the input voltage and the difference
between the main and secondary inductor currents.
Two identical transconductance amplifiers integrate the
difference between the master and slave current-sense
signals. The summed output is internally connected to
CCI, allowing adjustment of the integration time constant
with a compensation network connected between CCI
and FB.
The resulting compensation current and voltage are
determined by the following equations:
I CCI = G M ( V CMP - V CMN ) - G M ( V CSP - V CSN )
V CCI = V FB + I CCI Z CCI
both MOSFETs, output capacitor ESR, and PC board
copper losses in the output and ground tend to raise the
switching frequency at higher output currents. Also, the
dead-time effect increases the effective on-time, reduc-
ing the switching frequency. It occurs only during forced-
PWM operation and dynamic output voltage transitions
when the inductor current reverses at light or negative
load currents. With reversed inductor current, the induc-
tor ’ s EMF causes LX to go high earlier than normal,
extending the on-time by a period equal to the DH-rising
dead time.
For loads above the critical conduction point, where the
dead-time effect is no longer a factor, the actual
switching frequency (per phase) is:
where Z CCI is the impedance at the CCI output. The
secondary on-time one-shot uses this integrated signal
(V CCI ) to set the secondary high-side MOSFETs on-time.
f SW =
( V OUT + V DROP 1 )
t ON ( V IN + V DROP 1 - V DROP 2 )
t ON ( 2 ND ) = K ? CCI
?
?
?
= K ? FB
? + K ?
?
?
?
?
?
I MAIN - I 2 ND = I MAIN ? 1 - ? MAIN ? ?
When the main and secondary current-sense signals
(V CM = V CMP - V CMN and V CS = V CSP - V CSM ) become
unbalanced, the transconductance amplifiers adjust the
secondary on-time, which increases or decreases the
secondary inductor current until the current-sense
signals are properly balanced:
? V + 0 . 075 V ?
V IN
? V + 0 . 075 V ? ? I CCI Z CCI ?
V IN V IN
= ( Main on ? time ) + ( Secondary Current
Balance Correction )
This algorithm results in a nearly constant switching
frequency and balanced inductor currents, despite the
lack of a fixed-frequency clock generator. The benefits of
a constant switching frequency are twofold: first, the
frequency can be selected to avoid noise-sensitive
regions such as the 455kHz IF band; second, the induc-
tor ripple-current operating point remains relatively con-
stant, resulting in easy design methodology and
predictable output-voltage ripple. The on-time one-shots
have good accuracy at the operating points specified in
the Electrical Characteristics . On-times at operating
where V DROP1 is the sum of the parasitic voltage drops in
the inductor discharge path, including synchronous recti-
fier, inductor, and PC board resistances; V DROP2 is the
sum of the parasitic voltage drops in the inductor charge
path, including high-side switch, inductor, and PC board
resistances; and t ON is the on-time as determined above.
Current Balance
Without active current-balance circuitry, the current
matching between phases depends on the MOSFET ’ s
on-resistance (R DS(ON) ), thermal ballasting, on-/off-time
matching, and inductance matching. For example, vari-
ation in the low-side MOSFET on-resistance (ignoring
thermal effects) results in a current mismatch that is
proportional to the on-resistance difference:
? ? R ? ?
? ? ? R 2 ND ? ? ?
However, mismatches between on-times, off-times, and
inductor values increase the worst-case current imbal-
ance, making it impossible to passively guarantee
accurate current balancing.
Table 6. Approximate K-Factor Errors
points far removed from the conditions specified in the
Electrical Characteristics can vary over a wider range. For
example, the 300kHz setting typically runs about 3%
slower with inputs much greater than 12V due to the very
short on-times required.
On-times translate only roughly to switching frequencies.
The on-times guaranteed in the Electrical Characteristics
are influenced by switching delays in the external high-
side MOSFET. Resistive losses, including the inductor,
TON
CONNECTION
V CC
Float
REF
GND
FREQUENCY
SETTING
(kHz)
100
200
300
550
K-FACTOR
(μs)
10
5
3.3
1.8
MAX
K-FACTOR
ERROR
(%)
±10
±10
±10
±12.5
26
______________________________________________________________________________________
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MAX1544ETL+ 功能描述:电压模式 PWM 控制器 Dual-Phase Quick-PWM Controller 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
MAX1544ETL+T 功能描述:电压模式 PWM 控制器 Dual-Phase Quick-PWM Controller 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
MAX1544ETL+TG075 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
MAX1544ETL-T 功能描述:电压模式 PWM 控制器 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
MAX1544EVKIT 制造商:Maxim Integrated Products 功能描述:DUAL-PHASE, QUICK-PWM CONTROLLER FOR AMD HAMM - Bulk
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