ETC MC34167

一 18-
、〈国外电子元器件)1997 年第 4 期
1997 年 4 月
·新特器件应用
功率升美铺餐器 MC34167、 MC33167
输系 S重怠其法用
南京航空航天大学自控系
纪宗南
摘要: MC34167/MC33167 是 Motorola 公司生产的高性能固定频率稳压控制器，内
含固定频率的振荡器和大电流开关管，内设过热、欠压保护电路，具有 DC-DC 变换
所需的主要功能，能完成降压、开压和极性变换功能。本文介绍了其内部工作原理，
并给出了实用电路。
关键词:稳压器
PWM
欠压锁定逐周期限流
MC34167 和 MC33167 是高性
V阳
能固定频率的功率开关调整器，它
具有 DC-DC 变换所需要的主要功
能，即能完成升压、降压和反极性变
换，因此广泛应用在汽车、微控制器
应用系统、仪表、工业用品及家用电
气等领域。
L
该芯片内含一个温度补偿的基
准电压、记录单脉冲的锁定脉冲宽
度调制器、片内定时元件的固定频
率振荡器、高增益误差放大器和一
个大电流输出开关管、用于保护芯
片的保护电路(逐个周期的电流限
图 2 MC34167/MC33167 的功能框图
止、欠电压锁定和热断路)。
MC34167 和 MC33167 功能框图如图 2
1 、芯片简介
所示。
1. 1 引脚图和引脚功能
1. 3 主要性能
M04167 和 Mα3167 引脚四日阁"标。
·输出电流大于 5.0A。
MC34167 和 MC33167 引脚功能
.片含固定频率的振荡器二
①电压反馈输入
·无需外部电阻分压器即可提供
亏]
②开关输出
5.05V 输出。
③地、
·外围元件少。
④输入电压/
.基准电压的精度为 2% 。
·输出占空比范围大，即从 0% 到
Vα
⑤补偿岁待机
图 1 MC34167/33167 引脚图1. 2 功能框图
95% 。
.逐个周期的电流限制。
.'.町
川 U 嘻气与~l)-可~'~'7X ~竟是专产苛飞
功率开关调整器 MC34167、 MC33167 的原理及其应用
·具有滞后的欠电压锁定。
一 19 一
MC34167 系列采用逐个周期限制电流
·片内具有热关断电路。
的办法防止输出开关晶体管超负荷与电流限
·工作电压范围宽，即从 7.5-40V。
制是通过对输出开关晶体管导通时电流增长
·待机方式下电源电流降到 36μAo
过程的检测而实现的。每当检测到过电流
·采用 5 引脚的 TO，，220 封装。
时，就断开使振荡器波形上升的开关。
集电极电流通过一个内部调节的电阻转
2、工作原理
换成电压。这个电压加到电流传感器的同相
从图 2 中看出，该芯片由振荡器、脉冲宽
端，并与反相端的基准电压进行比较。当电
度调制器、电流传感、误差放大器和基准电压
流限制门限(通常门限值设定为 4.3A) 到达
等组成。现对其中的主要电路作简要介绍。
时，比较器使 PWM 锁存器复位。
2.1 振荡器
2.4 误差放大器和基准电压
片含固定频率的振荡器是该芯片重要特
误差放大器是一个高增益放大器，该放
点之一，其振荡频率由电容器 G 和调定的恒
大器的特点是能提供 80dB 直流增益，单位
流源决定 (72kHz) 。只要控制充、放电的比例
增益带宽在 70。相位裕度时为 600kHz 。同相
就可以在开关输出使最大占空比为 95% 。在
输入偏置值是由片内 5.05V 基准电压提供
G 放电时，振荡器产生一个内部空脉冲，它使
的，它不用引脚引到外面。基准电压在室温
与门的反相输入保持为高电平，使输出开关晶
下的精度为:t 2. 0% ，由于要向负载提供 5V
体管截止。可从时序图 3 中看出振荡器的峰、
电压，所以基准电压值必须较输出电压 (5V)
谷门限的标称值分别为 4.1V 和 2.3V。
高出 50mV，这个 50mV 用来补偿来自变换
2.2 脉冲宽度调制器
器输出电缆和接头上的压降二如果设计要求
脉冲宽度调制器是由一个比较器组成。
输出电压大于 5.0饥T， 则必须增加一个电阻
振荡器的锯齿电压加到它的同相输入端，而
Rl ， 以便在反馈输入形成一个分压网络。采
误差放大器的输出馈入到它的反相输入端。
用分压后，计算输出电压的公式如下:
输出开关的导通是当 G 放电达到振荡器的
谷底电压时开始的。当 CT 充电超过误差放
Vα厅=
R2
5. 05f一一+ 1)
Rl
大器的输出时，锁存器复位，结束振荡器波形
为了使变换器达到稳定状态，必须外接
的斜向上升阶段(此时输出晶体管导通)。这
补偿电阻 R2 和低通滤波器(~、 G) 。在选
种 PWM/ 锁存器的组合可以防止在一个给.
择电路中补偿元件值时，应保证在整个测试
定的振荡器时钟周期内输出多个脉冲。
2.3 电流传感器
工作条件下的稳定性。降压变换器是最容易
通过补偿来保证稳定性的，而升压变换器和
反极性变换器的补偿较
JLJYAJ
为叫要得到最佳网
络补偿，其简单的方法是
补偿一+
在负载逐步变化时观察
tl:!通一→·
一「产---， I
输出电压的响应，同时将
岛、 G 调整到临界阻尼
}1 关输出
断开-
'---J
L
图 3 日苦序图
值。最后的电路应在四种
边界条件(极小和极大负
一 20 一
〈国外电子元器件)1997 年第 4 期
1997 年 4 月
载下的极小和极大输出电压)下验证其稳定
由于该芯片是单片功率开关调整器§又具
性。如果将误差放大器的输出电压(引脚 5)
有 DC-OC 变换器的主要功能γ 所以应用极为
籍位到低于 15OmV，则内部电路将置于低功
广泛。现对其中的典型应用电路作些介绍。
耗待机方式，此时电源电流只有 36μA( 在
3.1 升/降压变换器
由 MC34167 和少量外围元件组成的升
12V 电源、条件下〉。
为了实现软起动，误差放大器的输出备
压/降压变换器如图 4 所示。从图中看出，该
有一个 100μA 的电流源。
电路与降压变换器相比较，只增加干个功率
2.5 欠电压锁定和热保护
MOSFET( 金属氧化物半导体场效应晶体
片内有一个欠电压锁定比较器，以保证
管)。在晶体管 Q1 和 Q2 导通时，能量存放在
在输出级恢复工作前集成电路是完全起作用
电感线圈中。在截止时，能量送到滤波电容
的。内部的 5.05V 基准电压由比较器监测，
和负载。这种电路结构与基本升压电路相比
它在 Vα 超过 5.9V 时使输出级恢复工作。为
较，有两个重要优点:①由 MC34167 提供输
了防止在跨越门限时输出切换不确定，提供
出短路保护，这是因为 Q1 直接和 V切及负载
了 0.9V 的滞后。
串联;②输出电压可低于 Vino
内部热保护电路是在结温超过最大值时
当 Vin 大于 20V 时， MOSFET 需要一个
保护集成电路的。在高温时(通常为 170"C ),
栅极保护网络，该网络由民、 D3 和 D4 组成，
迫使锁存器处于复位状态，使输出开关不工
如图中虚线所示。
该电路经实际测试，其结果如表 1 所
作，这样可以防止在器件过热时产生灾难性
后果，但它不能取代适当的散热器。
刁\0
'
3.2 三输出变换器
3 、典型应用
具有三路电压输出的变换器如图 5 所
~
lN驰22
.一-0
co 土+
n∞i
4.711
,1
图 4 升/降压变换器
L户半ι
,
~ R
1.511
Vo
28V.a.9A
功率开关调整器 MC34167 、 MC33167 的原理及其应用
-21 一
Vin
r--- 一---一-一-一-一一-一-一-------一-一-一---，
24V
1(i
乙士 1J1儿
6.8k
r一飞辛
~
川
iM
川川川
放川
1J点
i.t
VOl
5.0VI3 .OA
1 删主
L_ 一一一一一」一一-一一一一一一-牛
L 一一一一一二 J
--L
L一→←一一代灿一
68k
0.1
图 5 三路电压输出的变换器
表 1
测
时
线路调整
组的顶部，这样可以减少次级绕组的圈数并
升压/降压变换器测试结果
条
件
Vin = 1024V. Io = O. 9A 10mV=
改善引线的调整。为了获得最佳的辅助调
果
结
士 0.017%
Vin = 12V. Io = 0.10. 9P 国OmV= 士 0.053%
140mVp - p
输出纹披 VIN = 12V.. Io = O. 9A
6.0A
短路电流 V1N = 12V. RL = 0.1 .0
负载调整
,
效率
VIN = 12V. 10 = O. 9A
VIN = 24V. Io = O. 9A
80.1 %
87.8%
整，辅助输出应小于总功率的 33% 。
3.3 离线前置变换器
利用 MC34167 组成离线前置变换器的
电路如图 6 所示。该电路总功率为 125W，变
换效率为 90% 。图中变压器 T1 能使输出和
交流电路隔离，同时也使每个次级线圈彼此
」一
示。该电路具有三路电压输出，即 5.05V/
隔离。电路在 50kHz 时会产生自振，这可由
2. OA; 12V /300mA;一
12V/100mA。只要改
T2 的饱和和特性控制。本电路具有多个输
变次级绕绵的圈数，即可改变输出电压的大
出，从而可以为分布式功率系统提供多个独
小，这种多路输出在实际应用系统中是很受
立的精确调整器。
勘查理绩主棋锦5
欢迎的。
次级绕组的连接应该在开关断开时将能
(上接 P44)
量传送到次级输出。截止时，初级绕组上的
4 : 3 ，各种不同尺寸的有效感光面积如图 3 所
电压由反馈同路调节，产生一个恒定的伏特/
示，分别对应于1/4" ， 1/了，1/2"摄像机。
圈数比，任何给定的次级电压的圈数可以用
下式算出:
#圈数
VO(sÈC) + VF(SEU
( VIO(PR l> + VF<P'R I>、ì
飞 #圈数 PRl
i
,1
电路图中 12V 绕组连到 5.0V 绕
3.;!mm
48mm
. /1
罩/
I
./1
2.4mml 4,!)IIfm
3. 伽 ml.
6ω~
./
I
1/4"
图3
I
4.8mml
113"
的有效感片面积
CCD
..
1尼
•
7"?-
〈国外电子元器件)1997 年第 4 期
1997 年 4 月
a∞1
图 6 离线前置变换器
..叫....'.......'..~.....，.......，......唱'唱...啡唱'咖唱.......咱...啡..时，.咽'饨'唱'叶间...帽"
‘Þ-<....叫...啡.....唱'咱'而'咿......唱....'...'.，.........…~.....'..崎........................，.....什..咽..'.~...，...........，..
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•
、
1-9
SMPS 电路
功率开关调节器
MC33167/34167
MC34167/33167 系列是高性能、固定频率功率开关调节器 i 它包含 DC-DC( 直流到直流〉转换器所需的
俨)~
J俨 ι
主要功能。该系列器件外接元件极小，专门用于降压、升压和电压倒相。
特点 2
·贮存温度 T吨:一 65~ 十 150'C
封装:‘
·输出开关电流超过 5.0A
·具有片内定时的固定频率振荡器 (72kHz)
·带后缀 T 为塑封，外形图 :CASE 314D
.可提供不带外部电阻分压器的 5.05V 输出
·基准精度 2%
r 一←--一一一一一一一-一-一一一-一-一一 --1
·输出占空比 :O~95%
·循环周期的限流
!CrÎ
·内部过热断路保护
、
'--;:t i 开关.
三气工~A Urr----r一飞↓雪白
11椭
'------1
~Æ f!定 i
1 <:5号卜一I
二一一~
5.05V
二三一
+
平、
|
JUl
IιJ
l'
石正1
·电压反馈和补偿输入电压 V FB , V cornp :
斗斗料'←
I 川→fγJl牛~
rr=花一./
1 M:;调制器
.
·开关输出电压 V O (5wit出:一 2.0~+Vin
一1. O~+7.
L一一--.J
厂1;:-/
·备用方式可将电菁、电流降到 36μA
·电源电压 Vα:40V
I
;于江三
·工作电压 .7.5~40V
千 !fi
~一一一一，--------<，-/个一-寸→-0-→输入电压 IVct.
:~再副叫千叮「
·具有滞后的欠压锁定
极限参凯
电流传感A
A飞
VW1
脚咔〕
z1
I
LL:
11 L
L坐~I +i
误差
|φ| 电压反
量大\~高工
:
一、大寸寸丁十?-r-T←一个-o Vo
OW
·最大功耗 P D @T A=25'C: 1. 9W;
L______J 主
_l~ 一一一旦
咛
@TA=70'C:34. 7W
·热阻〈结到大气 )R创A@T A =25'C :65'C/\\
亨
·工作结温 T p 150'C
îCO
补偿仨-iLlLJ
j:)>- .仅正真逻键时
的陷电流
机
寸Y
·工作温度 T A :O~70'C
"2
(MC3416 7);
-40~+85'C (MC3316 7)
MC34167 电路功能框图
'
,
、
斗
二~咛‘
合
.'
主要电特性参数 (Vα=12V ，对于典型值， TA =25'C ，对于最小/最大值，飞为整个工作环境温度范围)
参
数
,
振荡器频率
条
Vcr. =7. 5-40V. TA=25'C
TA=TIo..-Thigh
'
误差放大摞电压反馈输入门限
TA=25'C
TA = Tlo..-Thig
5-40V , TA=25'C
线性调整
Vc汇 =7.
输入偏置电流
VFB = VFB(thl +0. 15V
电源抑制率
Vα=10-20V
输出电压摆幅
符号
最小值
典型值
最大值
单位
f"""
65
62
72
79
81
kHz
VFB(thl
4.95
4.85
5.05
5.15
5.20
V
RegJ ine
0.03
0.078
%/v
118
0.15
1.0
μA
PSRR
60
80
I.ource= 75μA ， VFB=4.7V
La nk=O. 4mA , VFB=5. 5V
VO H
VOL
4.2
待机
TA=25'C , Vtc= 12V. Vcomp<O. 15V
工作.
Vcr. =40V.1 端=地，用于最大占空比
Icc
4.9
1.6
36
40
离态
低态
整个器件电掠电流
件
dB
1.9
100
53
V
μA
mA
.l
LI 3 - 375
169
叮…-隘，
明耐-跚跚哥如
Table 7. Single龄 nded Controllers with On静 hip Power Switch
These monolithic power switching regulators contain all the active functions required to implement standard dc2!fu与c
∞ nverter configurations with a minimum number of external components
10
(mA)
Max
1500
(Uncommitted
Power Switch)
Maximum
Useful
Minimum
Operating
Voltage
Range
(V)
Operating
Mode
Reference
(V)
Frequency
(kHz)
Device
TA
(O C)
Suffixl
Package
2.5 to 40
Voltage
1.25 :l: 5.2%(1)
100
μA78 S40
o to +70
PC/648
。scillator
o to +85
1.25 :l: 2.0%
MC34063A
PV/648
o to +70
0/751
P1/626
MC33063A
o to +85
0/751
P1/626
o to +125
3.0 to 65
1500
Voltage
(Uncommi忧ed
Power Switch)
1.25 :l: 2.0%
and
5.05 :l: 30%
100
o to +70
P/648C ,
D叭11751G
MC33165
MC34163
2.5 to 40
3400
MC34165
0/751
o to +85
o to +70
(Uncommi忧ed
MC33163
Power Switch)
3400(2)
(Oedicated Emitter
Power Switch)
5.05 :l: 2.0%
7.5 to 40
72 土 12%
MC34166
Internally
Fixed
MC33166
o to +70
02T/936A ,
TH , TV,
MC34167
5500(3)
(Oedicated Emitter
Power Switch)
o to +85
MC33167
o to +85
T/3140
o to +70
o to +85
'
(1) Tolerance applies over the specified operating temperature range
(2) Guaranteed minimum , typically 4300 mA
(3) Guaranteed minimum , typically 6500 mA
Table 8. Easy Switcher™ Single龄 nded Controllers with On静 hip Power Switch
The Easy Switcher™ series is ideally suited for easy, convenient design of a step主bown switching regulator (buck converter) ,
with a minimum'number of external components
Minimum
。 perating
Voltage
Range
(V)
l。
(mA)
Max
1000
,
Oscillator
Frequency
(kHz)
Output
Voltage
(V)
Device
3.3
5.0
12
15
1.231037
LM2575T ..3
LM2575T
LM2575T 2
LM2575T 5
LM2575TlÞl dj
4.751040
8.01040
151040
181040
8.0 to 40
3.3
5.0
12
15
1.23 to 37
LM2575TV _.3
LM2575TV
LM2575TV 2
LM2575TV 5
4.75 to 40
8.0 to 40
15 to 40
18 to 40
8.0 to 40
3.3
5.0
12
15
1.23 to 37
LM257502T ..3
LM257502T
LM257502T 2
LM257502T 5
LM257502 Ttil dj
4.751040
8.0 to 40
151040
181040
8.0 to 40
Operating
Mode
Voltage
52 Fixed
Internal
ANALOG AND INTERFACE INTEGRATED CIRCUITS
SELECTOR GUIDE & CROSS REFERENCE
'
Suffixl
Package
TJ
(O C)
o to +125
T/3140
TV/314B
LM2575TVk时 dj
02T/936A
MOTOROLA
41
MC34167, MC33167
5.0 A, Step−Up/Down/
Inverting Switching
Regulators
The MC34167, MC33167 series are high performance fixed
frequency power switching regulators that contain the primary
functions required for dc−to−dc converters. This series was
specifically designed to be incorporated in step−down and
voltage−inverting configurations with a minimum number of external
components and can also be used cost effectively in step−up
applications.
These devices consist of an internal temperature compensated
reference, fixed frequency oscillator with on−chip timing components,
latching pulse width modulator for single pulse metering, high gain
error amplifier, and a high current output switch.
Protective features consist of cycle−by−cycle current limiting,
undervoltage lockout, and thermal shutdown. Also included is a low
power standby mode that reduces power supply current to 36 mA.
MARKING
DIAGRAMS
TO−220
TH SUFFIX
CASE 314A
1
5
MC
3x167T
AWLYWWG
Heatsink surface connected to Pin 3
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
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Output Switch Current in Excess of 5.0 A
Fixed Frequency Oscillator (72 kHz) with On−Chip Timing
Provides 5.05 V Output without External Resistor Divider
Precision 2% Reference
0% to 95% Output Duty Cycle
Cycle−by−Cycle Current Limiting
Undervoltage Lockout with Hysteresis
Internal Thermal Shutdown
Operation from 7.5 V to 40 V
Standby Mode Reduces Power Supply Current to 36 mA
Economical 5−Lead TO−220 Package with Two Optional Leadforms
Also Available in Surface Mount D2PAK Package
Moisture Sensitivity Level (MSL) Equals 1
Pb−Free Packages are Available
Vin
5
5
Pin
S
Q
1.
2.
3.
4.
5.
2
R
PWM
Thermal
MC
3x167T
AWLYWWG
Heatsink surface (shown as
terminal 6 in case outline
1
drawing) is connected to Pin 3
L
Reference
EA
1
VO
5.05 V/
5.0 A
5
This device contains 143 active transistors.
x
A
WL
Y
WW
G
5
= 3 or 4
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
ORDERING INFORMATION
Figure 1. Simplified Block Diagram
See detailed ordering and shipping information in the package
dimensions section on page 17 of this data sheet.
(Step Down Application)
November, 2005 − Rev. 7
MC
3x167T
AWLYWWG
5
UVLO
© Semiconductor Components Industries, LLC, 2005
MC
3x167T
AWLYWWG
Voltage Feedback Input
Switch Output
Ground
Input Voltage/VCC
Compensation/Standby
D2PAK
D2T SUFFIX
CASE 936A
1
3
TO−220
TV SUFFIX
CASE 314B
TO−220
T SUFFIX
CASE 314D
1
4
ILIMIT
Oscillator
1
1
Publication Order Number:
MC34167/D
MC34167, MC33167
MAXIMUM RATINGS (Note 1 and 2)
Rating
Power Supply Input Voltage
Switch Output Voltage Range
Symbol
Value
Unit
VCC
40
V
VO(switch)
−2.0 to + Vin
V
VFB, VComp
−1.0 to + 7.0
V
Power Dissipation
Case 314A, 314B and 314D (TA = +25°C)
Thermal Resistance, Junction−to−Ambient
Thermal Resistance, Junction−to−Case
Case 936A (D2PAK) (TA = +25°C)
Thermal Resistance, Junction−to−Ambient
Thermal Resistance, Junction−to−Case
PD
qJA
qJC
PD
qJA
qJC
Internally Limited
65
5.0
Internally Limited
70
5.0
W
°C/W
°C/W
W
°C/W
°C/W
Operating Junction Temperature
TJ
+150
°C
Operating Ambient Temperature (Note 3)
MC34167
MC33167
TA
Storage Temperature Range
Tstg
Voltage Feedback and Compensation Input Voltage Range
°C
0 to + 70
− 40 to + 85
− 65 to +150
°C
Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit
values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied,
damage may occur and reliability may be affected.
1. Maximum package power dissipation limits must be observed to prevent thermal shutdown activation.
2. This device series contains ESD protection and exceeds the following tests:
Human Body Model 2000 V per MIL−STD−883, Method 3015.
Machine Model Method 200 V.
3. Tlow = 0°C for MC34167
Thigh = + 70°C for MC34167
= − 40°C for MC33167
= + 85°C for MC33167
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2
MC34167, MC33167
ELECTRICAL CHARACTERISTICS (VCC = 12 V, for typical values TA = +25°C, for min/max values TA is the operating ambient
temperature range that applies (Notes 4, 5), unless otherwise noted.)
Symbol
Min
Typ
Max
Unit
TA = +25°C
TA = Tlow to Thigh
fOSC
65
62
72
−
79
81
kHz
TA =+ 25°C
TA = Tlow to Thigh
VFB(th)
4.95
4.85
5.05
−
5.15
5.20
V
Regline
−
0.03
0.078
%/V
Characteristic
OSCILLATOR
Frequency (VCC = 7.5 V to 40 V)
ERROR AMPLIFIER
Voltage Feedback Input Threshold
Line Regulation (VCC = 7.5 V to 40 V, TA = +25°C)
Input Bias Current (VFB = VFB(th) + 0.15 V)
Power Supply Rejection Ratio (VCC = 10 V to 20 V, f = 120 Hz)
Output Voltage Swing
High State (ISource = 75 mA, VFB = 4.5 V)
Low State (ISink = 0.4 mA, VFB = 5.5 V)
IIB
−
0.15
1.0
mA
PSRR
60
80
−
dB
VOH
VOL
4.2
−
4.9
1.6
−
1.9
V
DC(max)
DC(min)
92
0
95
0
100
0
%
Vsat
−
(VCC −1.5)
(VCC −1.8)
V
PWM COMPARATOR
Duty Cycle (VCC = 20 V)
Maximum (VFB = 0 V)
Minimum (VComp = 1.9 V)
SWITCH OUTPUT
Output Voltage Source Saturation (VCC = 7.5 V, ISource = 5.0 A)
Isw(off)
−
0
100
mA
Ipk(switch)
5.5
6.5
8.0
A
tr
tf
−
−
100
50
200
100
Startup Threshold (VCC Increasing, TA = +25°C)
Vth(UVLO)
5.5
5.9
6.3
V
Hysteresis (VCC Decreasing, TA = +25°C)
VH(UVLO)
0.6
0.9
1.2
V
−
−
36
40
100
60
mA
mA
Off−State Leakage (VCC = 40 V, Pin 2 = GND)
Current Limit Threshold (VCC = 7.5 V)
Switching Times (VCC = 40 V, Ipk = 5.0 A, L = 225 mH, TA = +25°C)
Output Voltage Rise Time
Output Voltage Fall Time
ns
UNDERVOLTAGE LOCKOUT
TOTAL DEVICE
Power Supply Current (TA = +25°C )
Standby (VCC = 12 V, VComp < 0.15 V)
Operating (VCC = 40 V, Pin 1 = GND for maximum duty cycle)
ICC
4. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
5. Tlow = 0°C for MC34167
Thigh = + 70°C for MC34167
= − 40°C for MC33167
= + 85°C for MC33167
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3
5.25
100
VCC = 12 V
I IB, INPUT BIAS CURRENT (nA)
VFB(th) Max = 5.15 V
5.17
5.09
VFB(th) Typ = 5.05 V
5.01
VFB(th) Min = 4.95 V
4.93
4.85
−55
−25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
60
40
20
Figure 2. Voltage Feedback Input Threshold
versus Temperature
80
Gain
VCC = 12 V
VComp = 3.25 V
RL = 100 k
TA = +25°C
0
30
60
60
40
90
Phase
20
120
0
150
−20
10
100
1.0 k
10 k
100 k
f, FREQUENCY (Hz)
180
10 M
1.0 M
DC, SWITCH OUTPUT DUTY CYCLE (%)
Δ f OSC, OSCILLATOR FREQUENCY CHANGE (%)
−4.0
−8.0
0
25
50
75
100
TA, AMBIENT TEMPERATURE (°C)
125
1.2
0.8
VCC = 12 V
VFB = 5.5 V
TA = +25°C
0.4
0
0.4
0.8
1.2
1.6
ISink, OUTPUT SINK CURRENT (mA)
2.0
Figure 5. Error Amp Output Saturation
versus Sink Current
VCC = 12 V
−25
100
1.6
0
4.0
−12
−55
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
2.0
Figure 4. Error Amp Open Loop Gain and
Phase versus Frequency
0
−25
Figure 3. Voltage Feedback Input Bias
Current versus Temperature
φ, EXCESS PHASE (DEGREES)
100
A VOL , OPEN LOOP VOLTAGE GAIN (dB)
VCC = 12 V
VFB = VFB(th)
80
0
−55
125
Vsat , OUTPUT SATURATION VOLTAGE (V)
V FB(th), VOLTAGE FEEDBACK INPUT THRESHOLD (V)
MC34167, MC33167
100
80
60
40
20
0
1.5
125
VCC = 12 V
TA = +25°C
Figure 6. Oscillator Frequency Change
versus Temperature
2.0
2.5
3.0
3.5
4.0
VComp, COMPENSATION VOLTAGE (V)
Figure 7. Switch Output Duty Cycle
versus Compensation Voltage
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4
4.5
0
0
VCC
−0.5
Vsw, SWITCH OUTPUT VOLTAGE (V)
Vsat, SWITCH OUTPUT SOURCE SATURATION (V)
MC34167, MC33167
TA = +25°C
−1.0
−1.5
−2.0
−2.5
−3.0
0
2.0
4.0
6.0
ISource, SWITCH OUTPUT SOURCE CURRENT (A)
GND
−0.2
VCC = 12 V
Pin 5 = 2.0 V
Pins 1, 3 = GND
Pin 2 Driven Negative
−0.4
−0.6
−0.8
Isw = 10 mA
−1.0
−1.2
−55
8.0
7.2
100
125
6.8
6.4
6.0
−25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
Pin 4 = VCC
Pins 1, 3, 5 = GND
Pin 2 Open
TA = +25°C
120
80
40
0
0
125
Figure 10. Switch Output Current Limit
Threshold versus Temperature
10
20
30
VCC, SUPPLY VOLTAGE (V)
40
Figure 11. Standby Supply Current
versus Supply Voltage
6.5
50
Startup Threshold
VCC Increasing
6.0
I CC, SUPPLY CURRENT (mA)
V th(UVLO) , UNDERVOLTAGE LOCKOUT THRESHOLD (V)
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
160
VCC = 12 V
Pins 1, 2, 3 = GND
5.5
Turn−Off Threshold
VCC Decreasing
5.0
4.5
4.0
−55
−25
Figure 9. Negative Switch Output Voltage
versus Temperature
I CC , SUPPLY CURRENT (μ A)
I pk(switch), CURRENT LIMIT THRESHOLD (A)
Figure 8. Switch Output Source Saturation
versus Source Current
5.6
−55
Isw = 100 mA
−25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
40
30
20
10
0
125
Pin 4 = VCC
Pins 1, 3 = GND
Pins 2, 5 Open
TA = +25°C
0
Figure 12. Undervoltage Lockout
Thresholds versus Temperature
10
20
30
VCC, SUPPLY VOLTAGE (V)
Figure 13. Operating Supply Current
versus Supply Voltage
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5
40
MC34167, MC33167
Vin
Current
Sense
+
4
Input Voltage/V CC
Cin
Oscillator
S
CT
Switch
Output
Q
R
Pulse Width
Modulator
2
Undervoltage
Lockout
PWM Latch
Thermal
Shutdown
L
5.05 V
Reference
+
+
Error
Amp
100 mA
3
Compensation
=
5
CF
RF
Sink Only
Positive True Logic
Figure 14. MC34167 Representative Block Diagram
4.1 V
Timing Capacitor CT
Compensation
2.3 V
ON
Switch Output
OFF
Figure 15. Timing Diagram
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6
R2
1
120
GND
Voltage
Feedback
Input
R1
VO
CO
MC34167, MC33167
INTRODUCTION
The MC34167, MC33167 series are monolithic power
switching regulators that are optimized for dc−to−dc
converter applications. These devices operate as fixed
frequency, voltage mode regulators containing all the active
functions required to directly implement step−down and
voltage−inverting converters with a minimum number of
external components. They can also be used cost effectively
in step−up converter applications. Potential markets include
automotive, computer, industrial, and cost sensitive
consumer products. A description of each section of the
device is given below with the representative block diagram
shown in Figure 14.
Figure 10 illustrates switch output current limit threshold
versus temperature.
Error Amplifier and Reference
A high gain Error Amplifier is provided with access to the
inverting input and output. This amplifier features a typical
dc voltage gain of 80 dB, and a unity gain bandwidth of
600 kHz with 70 degrees of phase margin (Figure 4). The
noninverting input is biased to the internal 5.05 V reference
and is not pinned out. The reference has an accuracy of
± 2.0% at room temperature. To provide 5.0 V at the load,
the reference is programmed 50 mV above 5.0 V to
compensate for a 1.0% voltage drop in the cable and
connector from the converter output. If the converter design
requires an output voltage greater than 5.05 V, resistor R1
must be added to form a divider network at the feedback
input as shown in Figures 14 and 19. The equation for
determining the output voltage with the divider network is:
Oscillator
The oscillator frequency is internally programmed to
72 kHz by capacitor CT and a trimmed current source. The
charge to discharge ratio is controlled to yield a 95%
maximum duty cycle at the Switch Output. During the
discharge of CT, the oscillator generates an internal blanking
pulse that holds the inverting input of the AND gate high,
disabling the output switch transistor. The nominal
oscillator peak and valley thresholds are 4.1 V and 2.3 V
respectively.
ǒ
Ǔ
R
Vout + 5.05 2 ) 1
R1
External loop compensation is required for converter
stability. A simple low−pass filter is formed by connecting
a resistor (R2) from the regulated output to the inverting
input, and a series resistor−capacitor (RF, CF) between Pins
1 and 5. The compensation network component values
shown in each of the applications circuits were selected to
provide stability over the tested operating conditions. The
step−down converter (Figure 19) is the easiest to
compensate for stability. The step−up (Figure 21) and
voltage−inverting (Figure 23) configurations operate as
continuous conduction flyback converters, and are more
difficult to compensate. The simplest way to optimize the
compensation network is to observe the response of the
output voltage to a step load change, while adjusting RF and
CF for critical damping. The final circuit should be verified
for stability under four boundary conditions. These
conditions are minimum and maximum input voltages, with
minimum and maximum loads.
By clamping the voltage on the error amplifier output
(Pin 5) to less than 150 mV, the internal circuitry will be
placed into a low power standby mode, reducing the
power supply current to 36 mA with a 12 V supply voltage.
Figure 11 illustrates the standby supply current versus
supply voltage.
The Error Amplifier output has a 100 mA current source
pull−up that can be used to implement soft−start. Figure 18
shows the current source charging capacitor CSS through a
series diode. The diode disconnects CSS from the feedback
loop when the 1.0 M resistor charges it above the operating
range of Pin 5.
Pulse Width Modulator
The Pulse Width Modulator consists of a comparator with
the oscillator ramp voltage applied to the noninverting input,
while the error amplifier output is applied into the inverting
input. Output switch conduction is initiated when CT is
discharged to the oscillator valley voltage. As CT charges to
a voltage that exceeds the error amplifier output, the latch
resets, terminating output transistor conduction for the
duration of the oscillator ramp−up period. This PWM/Latch
combination prevents multiple output pulses during a given
oscillator clock cycle. Figures 7 and 15 illustrate the switch
output duty cycle versus the compensation voltage.
Current Sense
The MC34167 series utilizes cycle−by−cycle current
limiting as a means of protecting the output switch transistor
from overstress. Each on cycle is treated as a separate
situation. Current limiting is implemented by monitoring the
output switch transistor current buildup during conduction,
and upon sensing an overcurrent condition, immediately
turning off the switch for the duration of the oscillator
ramp−up period.
The collector current is converted to a voltage by an
internal trimmed resistor and compared against a reference
by the Current Sense comparator. When the current limit
threshold is reached, the comparator resets the PWM latch.
The current limit threshold is typically set at 6.5 A.
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MC34167, MC33167
Switch Output
functional before the output stage is enabled. The internal
reference voltage is monitored by the comparator which
enables the output stage when VCC exceeds 5.9 V. To prevent
erratic output switching as the threshold is crossed, 0.9 V of
hysteresis is provided.
The output transistor is designed to switch a maximum of
40 V, with a minimum peak collector current of 5.5 A. When
configured for step−down or voltage−inverting applications,
as in Figures 19 and 23, the inductor will forward bias the
output rectifier when the switch turns off. Rectifiers with a
high forward voltage drop or long turn on delay time should
not be used. If the emitter is allowed to go sufficiently
negative, collector current will flow, causing additional
device heating and reduced conversion efficiency. Figure 9
shows that by clamping the emitter to 0.5 V, the collector
current will be in the range of 100 mA over temperature. A
1N5825 or equivalent Schottky barrier rectifier is
recommended to fulfill these requirements.
Thermal Protection
Internal Thermal Shutdown circuitry is provided to protect
the integrated circuit in the event that the maximum junction
temperature is exceeded. When activated, typically at 170°C,
the latch is forced into a ‘reset’ state, disabling the output
switch. This feature is provided to prevent catastrophic
failures from accidental device overheating. It is not
intended to be used as a substitute for proper heatsinking.
The MC34167 is contained in a 5−lead TO−220 type package.
The tab of the package is common with the center pin (Pin 3)
and is normally connected to ground.
Undervoltage Lockout
An Undervoltage Lockout comparator has been
incorporated to guarantee that the integrated circuit is fully
DESIGN CONSIDERATIONS
tight component layout is recommended. Capacitors Cin,
CO, and all feedback components should be placed as close
to the IC as physically possible. It is also imperative that the
Schottky diode connected to the Switch Output be located as
close to the IC as possible.
Do not attempt to construct a converter on wire−wrap
or plug−in prototype boards. Special care should be taken
to separate ground paths from signal currents and ground
paths from load currents. All high current loops should be
kept as short as possible using heavy copper runs to
minimize ringing and radiated EMI. For best operation, a
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8
MC34167, MC33167
+
Error
Amp
100 mA
+
Error
Amp
100 mA
120
Compensation
Compensation
1
120
1
5
R1
5
R1
I = Standby Mode
VShutdown = VZener + 0.7
Figure 17. Over Voltage Shutdown Circuit
Figure 16. Low Power Standby Circuit
+
Error
Amp
100 mA
1
120
Compensation
D2
5
R1
D1
Vin
1.0 M
Css
tSoft−Start ≈ 35,000 Css
Figure 18. Soft−Start Circuit
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9
MC34167, MC33167
Vin
12 V
+
4
ILIMIT
+
Oscillator
Cin
330
S
Q1
Q
R
2
PWM
D1
1N5825
UVLO
L
190 mH
Thermal
Reference
+
+
EA
R2
5
3
Test
CF
RF
0.1
68 k
CO
4700
6.8 k
1
VO
5.05 V/5.0 A
+
R1
Conditions
Results
Line Regulation
Vin = 10 V to 36 V, IO = 5.0 A
4.0 mV = ± 0.039%
Load Regulation
Vin = 12 V, IO = 0.25 A to 5.0 A
1.0 mV = ± 0.01%
Output Ripple
Vin = 12 V, IO = 5.0 A
20 mVpp
Short Circuit Current
Vin = 12 V, RL = 0.1 W
6.5 A
Efficiency
Vin = 12 V, IO = 5.0 A
Vin = 24 V, IO = 5.0 A
78.9%
82.6%
L = Coilcraft M1496−A or General Magnetics Technology GMT−0223, 42 turns of #16 AWG
on Magnetics Inc. 58350−A2 core. Heatsink = AAVID Engineering Inc. 5903B, or 5930B.
The Step−Down Converter application is shown in Figure 19. The output switch transistor Q1 interrupts the input voltage, generating a
squarewave at the LCO filter input. The filter averages the squarewaves, producing a dc output voltage that can be set to any level between
Vin and Vref by controlling the percent conduction time of Q1 to that of the total oscillator cycle time. If the converter design requires an output
voltage greater than 5.05 V, resistor R1 must be added to form a divider network at the feedback input.
Figure 19. Step−Down Converter
+
−
+
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉ
ÉÉÉÉÉ
ÉÉÉ
+
R2
−
VO
CO
Vin
1.9 ″
+
(Bottom View)
D1
R1
L
CF
RF
Cin
MC34167 STEP−DOWN
3.0″
(Top View)
Figure 20. Step−Down Converter Printed Circuit Board and Component Layout
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10
MC34167, MC33167
Vin
12 V
+
4
ILIMIT
+
Oscillator
Cin
330
S
D1
1N5825
Q1
Q
R
2
PWM
L
190 mH
UVLO
*RG
620
D4
1N4148
Thermal
Q2
MTP3055EL
Reference
+
D3
1N967A
+
D2
1N5822
EA
R2
1
CF
RF
0.47
4.7 k
5
3
+
VO
28 V/0.9 A
R1
1.5 k
*Gate resistor RG, zener diode D3, and diode D4 are required only when Vin is greater than 20 V.
Test
CO
2200
6.8 k
Conditions
Results
Line Regulation
Vin = 10 V to 24 V, IO = 0.9 A
10 mV = ± 0.017%
Load Regulation
Vin = 12 V, IO = 0.1 A to 0.9 A
30 mV = ± 0.053%
Output Ripple
Vin = 12 V, IO = 0.9 A
140 mVpp
Short Circuit Current
Vin = 12 V, RL = 0.1 W
6.0 A
Efficiency
Vin = 12 V, IO = 0.9 A
Vin = 24 V, IO = 0.9 A
80.1%
87.8%
L = Coilcraft M1496−A or General Magnetics Technology GMT−0223, 42 turns of #16 AWG on
Magnetics Inc. 58350−A2 core.
Heatsink = AAVID Engineering Inc. MC34167: 5903B, or 5930B MTP3055EL: 5925B
Figure 21 shows that the MC34167 can be configured as a step−up/down converter with the addition of an external power MOSFET. Energy
is stored in the inductor during the ON time of transistors Q1 and Q2. During the OFF time, the energy is transferred, with respect to ground,
to the output filter capacitor and load. This circuit configuration has two significant advantages over the basic step−up converter circuit. The first
advantage is that output short circuit protection is provided by the MC34167, since Q1 is directly in series with Vin and the load. Second, the
output voltage can be programmed to be less than Vin. Notice that during the OFF time, the inductor forward biases diodes D1 and D2, transferring
its energy with respect to ground rather than with respect to Vin. When operating with Vin greater than 20 V, a gate protection network is required
for the MOSFET. The network consists of components RG, D3, and D4.
D3
ÎÎÎÎÎ
ÎÎÎÎÎ
ÎÎÎÎÎ
ÎÎÎÎÎ
ÎÎÎÎÎ
ÎÎÎ
ÎÎÎÎÎ
ÎÎÎ
R2
+
+
(Bottom View)
CF
R1
+
D1
Cin
RF
D2
(Top View)
Figure 22. Step−Up/Down Converter Printed Circuit Board and Component Layout
http://onsemi.com
11
Î
Î
ÎÎ
Î
ÎÎ
Î
ÎÎ
Î
Q2
−
−
CO
Vin
VO
L
+
1.9″
3.45
″
MC34167 STEP UP-DOWN
Figure 21. Step−Up/Down Converter
RG
MC34167, MC33167
Vin
12 V
+
4
ILIMIT
+
Oscillator
Cin
330
S
Q1
Q
R
2
PWM
UVLO
L
190 mH
D1
1N5825
Thermal
Reference
+
+
EA
R1
5
3
Test
CF
RF
0.47
4.7 k
2.4 k
VO
−12 V/1.7 A
CO
4700
+
1
C1
R2
3.3 k
Conditions
0.047
Results
Line Regulation
Vin = 10 V to 24 V, IO = 1.7 A
15 mV = ± 0.61%
Load Regulation
Vin = 12 V, IO = 0.1 A to 1.7 A
4.0 mV = ± 0.020%
Output Ripple
Vin = 12 V, IO = 1.7 A
78 mVpp
Short Circuit Current
Vin = 12 V, RL = 0.1 W
5.7 A
Efficiency
Vin = 12 V, IO = 1.7 A
Vin = 24 V, IO = 1.7 A
79.5%
86.2%
L = Coilcraft M1496−A or General Magnetics Technology GMT−0223, 42 turns of #16 AWG on
Magnetics Inc. 58350−A2 core. Heatsink = AAVID Engineering Inc. 5903B, or 5930B.
Two potential problems arise when designing the standard voltage−inverting converter with the MC34167. First, the Switch Output emitter is
limited to −1.5 V with respect to the ground pin and second, the Error Amplifier’s noninverting input is internally committed to the reference and
is not pinned out. Both of these problems are resolved by connecting the IC ground pin to the converter’s negative output as shown in Figure 23.
This keeps the emitter of Q1 positive with respect to the ground pin and has the effect of reversing the Error Amplifier inputs. Note that the voltage
drop across R1 is equal to 5.05 V when the output is in regulation.
Figure 23. Voltage−Inverting Converter
3.0″
+
+
+
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎ
ÎÎÎÎÎÎ
Cin
CF
+
+
(Bottom View)
L
RF
D1
R2
−
CO
VO
−
R1
C1
+
Vin
1.9 ″
MC34167
VOLTAGE-INVERTING
+
(Top View)
Figure 24. Voltage−Inverting Converter Printed Circuit Board and Component Layout
http://onsemi.com
12
+
MC34167, MC33167
Vin
24 V
+
4
ILIMIT
+
Oscillator
1000
S
Q
R
2
PWM
1N5825
UVLO
MUR110
VO3
1000 −12 V/200 mA
+
Thermal
T1
Reference
+
MUR110
VO2
+
1000 12 V/250 mA
+
EA
6.8 k
1
1000
+
VO1
5.0 V/3.0 A
5
3
0.1
68 k
Figure 25. Triple Output Converter
Tests
Conditions
Results
Line Regulation
5.0 V
12 V
−12 V
Vin = 15 V to 30 V, IO1 = 3.0 A, IO2 = 250 mA, IO3 = 200 mA
3.0 mV = ± 0.029%
572 mV = ± 2.4%
711 mV = ± 2.9%
Load Regulation
5.0 V
12 V
−12 V
Vin = 24 V, IO1 = 30 mA to 3.0 A, IO2 = 250 mA, IO3 = 200 mA
Vin = 24 V, IO1 = 3.0 A, IO2 = 100 mA to 250 mA, IO3 = 200 mA
Vin = 24 V, IO1 = 3.0 A, IO2 = 250 mA, IO3 = 75 mA to 200 mA
1.0 mV = ± 0.009%
409 mV = ±1.5%
528 mV = ± 2.0%
Output Ripple
5.0 V
12 V
−12 V
Vin = 24 V, IO1 = 3.0 A, IO2 = 250 mA, IO3 = 200 mA
75 mVpp
20 mVpp
20 mVpp
Short Circuit Current
5.0 V
12 V
−12 V
Vin = 24 V, RL = 0.1 W
6.5 A
2.7 A
2.2 A
Vin = 24 V, IO1 = 3.0 A, IO2 = 250 mA, IO3 = 200 mA
84.2%
Efficiency
TOTAL
T1 = Primary: Coilcraft M1496−A or General Magnetics Technology GMT−0223, 42 turns of #16 AWG on Magnetics Inc. 58350−A2 core.
T1 = Secondary: VO2 − 69 turns of #26 AWG
T1 = Secondary: VO3 − 104 turns of #28 AWG
Heatsink = AAVID Engineering Inc. 5903B, or 5930B.
Multiple auxiliary outputs can easily be derived by winding secondaries on the main output inductor to form a transformer. The secondaries
must be connected so that the energy is delivered to the auxiliary outputs when the Switch Output turns off. During the OFF time, the voltage
across the primary winding is regulated by the feedback loop, yielding a constant Volts/Turn ratio. The number of turns for any given secondary
voltage can be calculated by the following equation:
# TURNS(SEC) +
VO(SEC) ) VF(SEC)
VO(PRI))VF(PRI)
#TURNS(PRI)
ǒ
Ǔ
Note that the 12 V winding is stacked on top of the 5.0 V output. This reduces the number of secondary turns and improves lead regulation. For
best auxiliary regulation, the auxiliary outputs should be less than 33% of the total output power.
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13
MC34167, MC33167
+
4
ILIMIT
Oscillator
22
0.01
1N5825
S
Q1
Q
R
Ǔ
2
UVLO
PWM
ǒ
VO + 5.05
R1 ) 0.7
R2
L
D1
Thermal
+
R1
36 k
MTP
3055E
Reference
+
VO
+36 V/0.3 A
MUR415
R1
+
EA
Z1
2N3906
1
6.8 k
5
3
0.22
470 k
R2
5.1 k
0.002
Vin
−12 V
1000
+
*Gate resistor RG, zener diode D3, and diode D4 are required only when Vin is greater than 20 V.
Test
Conditions
Results
Line Regulation
Vin = −10 V to − 20 V, IO = 0.3 A
266 mV = ± 0.38%
Load Regulation
Vin = −12 V, IO = 0.03 A to 0.3 A
7.90 mV = ±1.1%
Output Ripple
Vin = −12 V, IO = 0.3 A
100 mVpp
Efficiency
Vin = −12 V, IO = 0.3 A
78.4%
L = General Magnetics Technology GMT−0223, 42 turns of #16 AWG on Magnetics Inc.
58350−A2 core. Heatsink = AAVID Engineering Inc. 5903B or 5930B
Figure 26. Negative Input/Positive Output Regulator
+
Vin
18 V
4
ILIMIT
+
Oscillator
1000
S
Q
R
UVLO
2
PWM
Brush
Motor
Thermal
Reference
+
EA
1N5825
+
1
5.6 k
1.0 k
+
47
5
3
0.1
56 k
Test
Conditions
Results
Low Speed Line Regulation
Vin = 12 V to 24 V
1760 RPM ±1%
High Speed Line Regulation
Vin = 12 V to 24 V
3260 RPM ± 6%
Figure 27. Variable Motor Speed Control with EMF Feedback Sensing
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14
50 k
Faster
1000
MC34167, MC33167
0.001
T1
MBR20100CT
+
1000
0.001
1N5404
MC34167
Step−Down
Converter
+
MC34167
Step−Down
Converter
+
MC34167
Step−Down
Converter
+
Output 1
0.001
RFI
115 VAC Filter
+
220
MJE13005
MBR20100CT
0.047
1N4937
100k
T2
+
1000
0.01
50
0.001
Output 2
0.001
3.3
+
100
1N4003
MBR20100CT
+
1000
0.001
T1 = Core and Bobbin − Coilcraft PT3595
T1 = Primary − 104 turns #26 AWG
T1 = Base Drive − 3 turns #26 AWG
T1 = Secondaries − 16 turns #16 AWG
T1 = Total Gap − 0.002,
Output 3
T2 = Core − TDK T6 x 1.5 x 3 H5C2
T2 = 14 turns center tapped #30 AWG
T2 = Heatsink = AAVID Engineering Inc.
T2 = MC34167 and MJE13005 − 5903B
T2 = MBR20100CT − 5925B
The MC34167 can be used cost effectively in off−line applications even though it is limited to a maximum input voltage of 40 V. Figure 28 shows
a simple and efficient method for converting the AC line voltage down to 24 V. This preconverter has a total power rating of 125 W with a
conversion efficiency of 90%. Transformer T1 provides output isolation from the AC line and isolation between each of the secondaries. The
circuit self−oscillates at 50 kHz and is controlled by the saturation characteristics of T2. Multiple MC34167 post regulators can be used to provide
accurate independently regulated outputs for a distributed power system.
JUNCTION-TO-AIR (° C/W)
R θ JA, THERMAL RESISTANCE
80
3.5
PD(max) for TA = +50°C
70
3.0
Free Air
Mounted
Vertically
60
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
2.0 oz. Copper
L
Minimum
Size Pad
50
2.5
2.0
L
40
1.5
RqJA
30
1.0
0
5.0
10
15
20
25
30
L, LENGTH OF COPPER (mm)
Figure 29. D2PAK Thermal Resistance and Maximum
Power Dissipation versus P.C.B. Copper Length
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15
PD, MAXIMUM POWER DISSIPATION (W)
Figure 28. Off−Line Preconverter
MC34167, MC33167
Table 1. Design Equations
Calculation
Step−Down
Step−Up/Down
Voltage−Inverting
ton
toff
(Notes 1, 2)
Vout ) VF
Vin * Vsat * Vout
Vout ) VF1 ) VF2
Vin * VsatQ1 * VsatQ2
|Vout| ) VF
Vin * Vsat
ton
ton
toff
ton
fosc
)1
toff
ton
toff
ton
fosc
)1
toff
ton
toff
ton
fosc
)1
toff
Duty Cycle
(Note 3)
ton fosc
ton fosc
ton fosc
IL avg
Iout
t
Iout on ) 1
toff
t
Iout on ) 1
toff
Ipk(switch)
DI
IL avg ) L
2
DI
IL avg ) L
2
DI
IL avg ) L
2
L
ǒVin * VDIsatL * VoutǓton
* VsatQ2
ǒVin * VsatQ1
Ǔton
DIL
ǒVin *DILVsatǓton
Vripple(pp)
Vout
ǒ
DIL
Ǹǒ
Ǔ
ǒ
Ǔ
1
2 ) (ESR)2
8foscCo
ǒ
ǒ
Ǔ
R
Vref 2 ) 1
R1
Ǔ
Ǔ
ǒtton
) 1Ǔ Ǹǒ 1 Ǔ2 ) (ESR)2
foscCo
off
ǒ
Ǔ
R
Vref 2 ) 1
R1
ǒ
ǒ
Ǔ
Ǔ
ǒtton
) 1Ǔ Ǹǒ 1 Ǔ2 ) (ESR)2
foscCo
off
ǒ
Ǔ
R
Vref 2 ) 1
R1
1. Vsat − Switch Output source saturation voltage, refer to Figure 8.
2. VF − Output rectifier forward voltage drop. Typical value for 1N5822 Schottky barrier rectifier is 0.35 V.
3. Duty cycle is calculated at the minimum operating input voltage and must not exceed the guaranteed minimum DC(max) specification of 0.92.
The following converter characteristics must be chosen:
Vout − Desired output voltage.
Iout − Desired output current.
DIL − Desired peak−to−peak inductor ripple current. For maximum output current especially when the duty cycle is greater than 0.5,
it is suggested that DIL be chosen minimum current limit threshold of 5.5 A. If the design goal is to use a minimum inductance
value, let DIL = 2 (IL avg). This will proportionally reduce the converter’s output current capability.
Vripple(pp) − Desired peak−to−peak output ripple voltage. For best performance, the ripple voltage should be kept to less than 2% of Vout.
Capacitor CO should be a low equivalent series resistance (ESR) electrolytic designed for switching regulator applications.
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16
MC34167, MC33167
ORDERING INFORMATION
Operating
Temperature Range
Package
Shipping †
MC33167D2T
D2PAK (Surface Mount)
50 Units / Rail
MC33167D2TG
D2PAK
MC33167D2TR4
D2PAK (Surface Mount)
MC33167D2TR4G
D2PAK
MC33167T
TO−220 (Straight Lead)
50 Units / Rail
TO−220 (Straight Lead)
(Pb−Free)
50 Units / Rail
MC33167TH
TO−220 (Horizontal Mount)
50 Units / Rail
MC33167THG
TO−220 (Horizontal Mount)
(Pb−Free)
50 Units / Rail
MC33167TV
TO−220 (Vertical Mount)
50 Units / Rail
MC33167TVG
TO−220 (Vertical Mount)
(Pb−Free)
50 Units / Rail
MC34167D2T
D2PAK (Surface Mount)
50 Units / Rail
MC34167D2TG
D2PAK (Surface Mount)
(Pb−Free)
50 Units / Rail
MC34167D2TR4
D2PAK (Surface Mount)
800 / Tape & Reel
MC34167D2TR4G
D2PAK
Device
MC33167TG
(Surface Mount)
(Pb−Free)
(Surface Mount)
(Pb−Free)
TA= −40° to +85°C
(Surface Mount)
(Pb−Free)
MC34167T
50 Units / Rail
800 / Tape & Reel
800 / Tape & Reel
800 / Tape & Reel
TO−220 (Straight Lead)
50 Units / Rail
TO−220 (Straight Lead)
(Pb−Free)
50 Units / Rail
MC34167TH
TO−220 (Horizontal Mount)
50 Units / Rail
MC34167THG
TO−220 (Horizontal Mount)
(Pb−Free)
50 Units / Rail
MC34167TV
TO−220 (Vertical Mount)
50 Units / Rail
MC34167TVG
TO−220 (Vertical Mount)
(Pb−Free)
50 Units / Rail
MC34167TG
TA= 0° to +70°C
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
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17
MC34167, MC33167
PACKAGE DIMENSIONS
TO−220
TH SUFFIX
CASE 314A−03
ISSUE E
−T−
B
−P−
Q
C
E
OPTIONAL
CHAMFER
A
U
F
L
G
DIM
A
B
C
D
E
F
G
J
K
L
Q
S
U
K
5X
J
S
D
5X
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION D DOES NOT INCLUDE
INTERCONNECT BAR (DAMBAR) PROTRUSION.
DIMENSION D INCLUDING PROTRUSION SHALL
NOT EXCEED 0.043 (1.092) MAXIMUM.
SEATING
PLANE
0.014 (0.356)
M
T P
M
INCHES
MIN
MAX
0.572
0.613
0.390
0.415
0.170
0.180
0.025
0.038
0.048
0.055
0.570
0.585
0.067 BSC
0.015
0.025
0.730
0.745
0.320
0.365
0.140
0.153
0.210
0.260
0.468
0.505
MILLIMETERS
MIN
MAX
14.529 15.570
9.906 10.541
4.318
4.572
0.635
0.965
1.219
1.397
14.478 14.859
1.702 BSC
0.381
0.635
18.542 18.923
8.128
9.271
3.556
3.886
5.334
6.604
11.888 12.827
TO−220
TV SUFFIX
CASE 314B−05
ISSUE L
OPTIONAL
CHAMFER
E
A
U
K
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION D DOES NOT INCLUDE
INTERCONNECT BAR (DAMBAR) PROTRUSION.
DIMENSION D INCLUDING PROTRUSION SHALL
NOT EXCEED 0.043 (1.092) MAXIMUM.
C
B
−P−
Q
S
L
W
V
F
5X
G
5X
0.24 (0.610)
M
J
T
H
D
0.10 (0.254)
M
T P
M
N
−T−
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18
SEATING
PLANE
DIM
A
B
C
D
E
F
G
H
J
K
L
N
Q
S
U
V
W
INCHES
MIN
MAX
0.572
0.613
0.390
0.415
0.170
0.180
0.025
0.038
0.048
0.055
0.850
0.935
0.067 BSC
0.166 BSC
0.015
0.025
0.900
1.100
0.320
0.365
0.320 BSC
0.140
0.153
−−−
0.620
0.468
0.505
−−−
0.735
0.090
0.110
MILLIMETERS
MIN
MAX
14.529 15.570
9.906 10.541
4.318
4.572
0.635
0.965
1.219
1.397
21.590 23.749
1.702 BSC
4.216 BSC
0.381
0.635
22.860 27.940
8.128
9.271
8.128 BSC
3.556
3.886
−−− 15.748
11.888 12.827
−−− 18.669
2.286
2.794
MC34167, MC33167
PACKAGE DIMENSIONS
TO−220
T SUFFIX
CASE 314D−04
ISSUE F
−T−
B
−Q−
DETAIL A−A
B1
SEATING
PLANE
C
E
A
U
L
J
H
G
D
DIM
A
B
B1
C
D
E
G
H
J
K
L
Q
U
1234 5
K
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION D DOES NOT INCLUDE
INTERCONNECT BAR (DAMBAR) PROTRUSION.
DIMENSION D INCLUDING PROTRUSION SHALL
NOT EXCEED 10.92 (0.043) MAXIMUM.
5 PL
0.356 (0.014)
M
T Q
M
B
B1
DETAIL A−A
http://onsemi.com
19
INCHES
MIN
MAX
0.572
0.613
0.390
0.415
0.375
0.415
0.170
0.180
0.025
0.038
0.048
0.055
0.067 BSC
0.087
0.112
0.015
0.025
0.977
1.045
0.320
0.365
0.140
0.153
0.105
0.117
MILLIMETERS
MIN
MAX
14.529 15.570
9.906 10.541
9.525 10.541
4.318
4.572
0.635
0.965
1.219
1.397
1.702 BSC
2.210
2.845
0.381
0.635
24.810 26.543
8.128
9.271
3.556
3.886
2.667
2.972
MC34167, MC33167
D2PAK
D2T SUFFIX
CASE 936A−02
ISSUE C
−T−
OPTIONAL
CHAMFER
A
E
U
S
K
B
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. TAB CONTOUR OPTIONAL WITHIN DIMENSIONS A
AND K.
4. DIMENSIONS U AND V ESTABLISH A MINIMUM
MOUNTING SURFACE FOR TERMINAL 6.
5. DIMENSIONS A AND B DO NOT INCLUDE MOLD
FLASH OR GATE PROTRUSIONS. MOLD FLASH
AND GATE PROTRUSIONS NOT TO EXCEED 0.025
(0.635) MAXIMUM.
TERMINAL 6
V
H
1 2 3 4 5
M
D
0.010 (0.254)
M
T
L
P
N
G
INCHES
MIN
MAX
0.386
0.403
0.356
0.368
0.170
0.180
0.026
0.036
0.045
0.055
0.067 BSC
0.539
0.579
0.050 REF
0.000
0.010
0.088
0.102
0.018
0.026
0.058
0.078
5 _ REF
0.116 REF
0.200 MIN
0.250 MIN
DIM
A
B
C
D
E
G
H
K
L
M
N
P
R
S
U
V
R
C
MILLIMETERS
MIN
MAX
9.804
10.236
9.042
9.347
4.318
4.572
0.660
0.914
1.143
1.397
1.702 BSC
13.691
14.707
1.270 REF
0.000
0.254
2.235
2.591
0.457
0.660
1.473
1.981
5 _ REF
2.946 REF
5.080 MIN
6.350 MIN
SOLDERING FOOTPRINT*
8.38
0.33
1.702
0.067
10.66
0.42
3.05
0.12
16.02
0.63
SCALE 3:1
1.016
0.04
mm Ǔ
ǒinches
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should
Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates,
and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal
Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
PUBLICATION ORDERING INFORMATION
LITERATURE FULFILLMENT:
N. American Technical Support: 800−282−9855 Toll Free
Literature Distribution Center for ON Semiconductor
USA/Canada
P.O. Box 61312, Phoenix, Arizona 85082−1312 USA
Phone: 480−829−7710 or 800−344−3860 Toll Free USA/Canada Japan: ON Semiconductor, Japan Customer Focus Center
2−9−1 Kamimeguro, Meguro−ku, Tokyo, Japan 153−0051
Fax: 480−829−7709 or 800−344−3867 Toll Free USA/Canada
Phone: 81−3−5773−3850
Email: [email protected]
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