參數(shù)資料
型號： DRV591VFP(1)
廠商： Texas Instruments, Inc.
元件分類： 繼電器，輸入/輸出模塊
英文描述： 30 AMP MINIATURE POWER RELAY
中文描述： 3 -一種高效的PWM功率驅(qū)動器
文件頁數(shù)： 12/16頁
文件大?。?/td> 141K
代理商： DRV591VFP(1)
SLOS389A
–
NOVEMBER 2001
–
REVISED MAY 2002
www.ti.com
12
LC FILTER IN THE FREQUENCY DOMAIN
The transfer function for a 2
nd
order low-pass filter (Figures
17 and 18) is shown in equation (2):
HLP(j )
1
–
0
2
1
Q
j
0
1
0
1
LC
quality factor
DRV591 switching frequency
Q
For the DRV591, the differential output switching
frequency is typically selected to be 500 kHz. The resonant
frequency for the filter is typically chosen to be at least one
order of magnitude lower than the switching frequency.
Equation (2) may then be simplified to give the following
magnitude equation (3). These equations assume the use
of the filter in Figure 17.
HLP dB
–
40 log
fs
fo
fo
1
2
500 kHz (DRV591 switching frequency)
LC
fs
If L=10
μ
H and C=10
μ
F, the cutoff frequency is 15.9 kHz,
which corresponds to
–
60 dB of attenuation at the 500 kHz
switching frequency. For VDD = 5 V, the amount of ripple
voltage at the TEC element is approximately 5 mV.
The average TEC element has a resistance of 1.5
, so the
ripple current through the TEC is approximately 3.4 mA. At
the 3-A maximum output current of the DRV591, this 5.4
mA corresponds to 0.11% ripple current, causing less than
0.0001% reduction of the maximum temperature
differential of the TEC element (see equation 1).
LC FILTER IN THE TIME DOMAIN
The ripple current of an inductor may be calculated using
equation (4):
IL
VO
–
VTECDTs
L
duty cycle (0.5 worst case)
D
T
s
1 f
s
1 500 kHz
For V
O
= 5 V, V
TEC
= 2.5 V, and L = 10
μ
H, the inductor
ripple current is 250 mA. To calculate how much of that
ripple current flows through the TEC element, however,
the properties of the filter capacitor must be considered.
For relatively small capacitors (less than 22
μ
F) with very
low equivalent series resistance (ESR, less than 10 m
),
such as ceramic capacitors, the following equation (5) may
be used to estimate the ripple voltage on the capacitor due
to the change in charge:
VC
2
2
1
–
D
fo
fs
2
VTEC
fo
1
2
LC
fs
500 kHz
D
duty cycle
For L = 10
μ
H and C = 10
μ
F, the cutoff frequency, f
o
, is 15.9
kHz. For worst case duty cycle of 0.5 and V
TEC
=2.5 V, the
ripple voltage on the capacitors is 6.2 mV. The ripple
current may be calculated by dividing the ripple voltage by
the TEC resistance of 1.5
, resulting in a ripple current
through the TEC element of 4.1 mA. Note that this is
similar to the value calculated using the frequency domain
approach.
For larger capacitors (greater than 22
μ
F) with relatively
high ESR (greater than 100 m
), such as electrolytic
capacitors, the ESR dominates over the charging-
discharging of the capacitor. The following simple equation
(6) may be used to estimate the ripple voltage:
VC
IL
IL
RESR
inductor ripple current
RESR
For a 100
μ
F electrolytic capacitor, an ESR of 0.1
is
common. If the 10
μ
H inductor is used, delivering 250 mA
of ripple current to the capacitor (as calculated above),
then the ripple voltage is 25 mV. This is over ten times that
of the 10
μ
F ceramic capacitor, as ceramic capacitors
typically have negligible ESR.
filter capacitor ESR
SWITCHING FREQUENCY CONFIGURATION:
OSCILLATOR COMPONENTS R
OSC
AND
C
OSC
AND FREQ OPERATION
The onboard ramp generator requires an external resistor
and capacitor to set the oscillation frequency. The
frequency may be either 500 kHz or 100 kHz by selecting
the proper capacitor value and by holding the FREQ pin
either low (500 kHz) or high (100 kHz). Table 1 shows the
values required and FREQ pin configuration for each
switching frequency.
Table 1. Frequency Configuration Options
SWITCHING
FREQUENCY
ROSC
COSC
FREQ
500 kHz
120 k
120 k
220 pF
LOW (GND)
100 kHz
1 nF
HIGH (VDD)
(2)
(3)
(4)
(5)
(6)
相關(guān)PDF資料
PDF描述
DRVM6.4B100N Analog IC
DRVM6.4B100P Analog IC
DRVM6.4B10N Analog IC
DRVM6.4B10P Analog IC
DRVM6.4B25N Analog IC
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DRV591VFPG4 功能描述:功率驅(qū)動器IC High Efficiency PWM Power Driver RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube
DRV591VFPR 功能描述:功率驅(qū)動器IC High Efficiency PWM Power Driver RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube
DRV591VFPRG4 功能描述:功率驅(qū)動器IC High Efficiency PWM Power Driver RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube
DRV592 制造商:TI 制造商全稱:Texas Instruments 功能描述:+- 3-A HIGH EFFICIENCY H-BRIDGE
DRV592EVM 功能描述:EVALUATION MODULE FOR DRV592 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 過時/停產(chǎn)零件編號 系列:- 標準包裝:1 系列:*
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。

采購需求

(若只采購一條型號，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進入我的后臺，查看報價

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進入我的后臺，查看報價

*型號 *數(shù)量 廠商 批號 封裝
添加更多采購

我的聯(lián)系方式

*
*
*