ON MC33167D2T Power switching regulator Datasheet

Order this document by MC34167/D
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 µA.
• Output Switch Current in Excess of 5.0 A
•
•
•
•
•
•
•
•
•
•
•
POWER SWITCHING
REGULATORS
SEMICONDUCTOR
TECHNICAL DATA
TH SUFFIX
PLASTIC PACKAGE
CASE 314A
Fixed Frequency Oscillator (72 kHz) with On–Chip Timing
Provides 5.05 V Output without External Resistor Divider
1
5
Precision 2% Reference
0% to 95% Output Duty Cycle
1
TV SUFFIX
PLASTIC PACKAGE
CASE 314B
Cycle–by–Cycle Current Limiting
5
Undervoltage Lockout with Hysteresis
Internal Thermal Shutdown
Heatsink surface connected to Pin 3.
Operation from 7.5 V to 40 V
Standby Mode Reduces Power Supply Current to 36 µA
Economical 5–Lead TO–220 Package with Two Optional Leadforms
Also Available in Surface Mount D2PAK Package
T SUFFIX
PLASTIC PACKAGE
CASE 314D
1
5
Pin 1.
2.
3.
4.
5.
Simplified Block Diagram
(Step Down Application)
Voltage Feedback Input
Switch Output
Ground
Input Voltage/VCC
Compensation/Standby
Vin
D2T SUFFIX
PLASTIC PACKAGE
CASE 936A
(D2PAK)
4
ILIMIT
1
Oscillator
5
S
Q
Heatsink surface (shown as terminal 6
in case outline drawing) is connected to Pin 3.
2
R
PWM
ORDERING INFORMATION
UVLO
Thermal
L
Reference
EA
1
3
5
This device contains 143 active transistors.
VO
5.05 V/5.0 A
Device
Operating
Temperature Range
Surface Mount
Straight Lead
Horiz. Mount
Vertical Mount
MC34167D2T
MC34167T
MC34167TH
MC34167TV
Surface Mount
Straight Lead
Horiz. Mount
Vertical Mount
TA = 0° to + 70°C
 Motorola, Inc. 1996
MOTOROLA ANALOG IC DEVICE DATA
Package
MC33167D2T
MC33167T
TA = – 40° to +85°C
MC33167TH
MC33167TV
Rev 3
1
MC34167 MC33167
MAXIMUM RATINGS
Rating
Symbol
Power Supply Input Voltage
Value
Unit
VCC
40
V
VO(switch)
–2.0 to + Vin
V
VFB, VComp
–1.0 to + 7.0
V
PD
θJA
θJC
PD
θJA
θJC
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
Switch Output Voltage Range
Voltage Feedback and Compensation Input
Voltage Range
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
°C
0 to + 70
– 40 to + 85
Storage Temperature Range
Tstg
– 65 to +150
°C
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 2, 3], unless otherwise noted.)
Characteristic
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
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 µA, VFB = 4.5 V)
Low State (ISink = 0.4 mA, VFB = 5.5 V)
IIB
–
0.15
1.0
µA
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
µA
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
µA
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 µH, 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
NOTES: 1. Maximum package power dissipation limits must be observed to prevent thermal shutdown activation.
2. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
3. Tlow = 0°C for MC34167
Thigh = + 70°C for MC34167
= – 40°C for MC33167
= + 85°C for MC33167
2
MOTOROLA ANALOG IC DEVICE DATA
Figure 1. Voltage Feedback Input Threshold
versus Temperature
Figure 2. Voltage Feedback Input Bias
Current versus Temperature
5.25
100
VCC = 12 V
VFB(th) Max = 5.15 V
I IB, INPUT BIAS CURRENT (nA)
V FB(th), VOLTAGE FEEDBACK INPUT THRESHOLD (V)
MC34167 MC33167
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
VCC = 12 V
VFB = VFB(th)
80
60
40
20
0
– 55
125
80
Gain
0
30
60
60
40
90
Phase
20
120
0
150
– 20
10
100
1.0 k
10 k
100 k
f, FREQUENCY (Hz)
1.0 M
180
10 M
125
1.6
1.2
0.8
VCC = 12 V
VFB = 5.5 V
TA = +25°C
0.4
0
Figure 5. Oscillator Frequency Change
versus Temperature
0.4
0.8
1.2
1.6
ISink, OUTPUT SINK CURRENT (mA)
2.0
Figure 6. Switch Output Duty Cycle
versus Compensation Voltage
100
4.0
VCC = 12 V
0
– 4.0
– 8.0
– 12
– 55
100
2.0
0
DC, SWITCH OUTPUT DUTY CYCLE (%)
∆ f OSC , OSCILLATOR FREQUENCY CHANGE (%)
VCC = 12 V
VComp = 3.25 V
RL = 100 k
TA = +25°C
Vsat , OUTPUT SATURATION VOLTAGE (V)
100
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
Figure 4. Error Amp Output Saturation
versus Sink Current
φ, EXCESS PHASE (DEGREES)
A VOL , OPEN LOOP VOLTAGE GAIN (dB)
Figure 3. Error Amp Open Loop Gain and
Phase versus Frequency
– 25
– 25
0
25
50
75
100
TA, AMBIENT TEMPERATURE (°C)
MOTOROLA ANALOG IC DEVICE DATA
125
80
VCC = 12 V
TA = +25°C
60
40
20
0
1.5
2.0
2.5
3.0
3.5
4.0
VComp, COMPENSATION VOLTAGE (V)
4.5
3
Figure 7. Switch Output Source Saturation
versus Source Current
Figure 8. Negative Switch Output Voltage
versus Temperature
0
0
VCC
Vsw, SWITCH OUTPUT VOLTAGE (V)
Vsat, SWITCH OUTPUT SOURCE SATURATION (V)
MC34167 MC33167
– 0.5
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
I pk(switch), CURRENT LIMIT THRESHOLD (A)
Figure 9. Switch Output Current Limit
Threshold versus Temperature
I CC , SUPPLY CURRENT ( µ A)
6.8
6.4
6.0
V th(UVLO) , UNDERVOLTAGE LOCKOUT THRESHOLD (V)
100
125
– 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 11. Undervoltage Lockout
Thresholds versus Temperature
10
20
30
VCC, SUPPLY VOLTAGE (V)
40
Figure 12. Operating Supply Current
versus Supply Voltage
6.5
50
I CC, SUPPLY CURRENT (mA)
Startup Threshold
VCC Increasing
6.0
5.5
Turn–Off Threshold
VCC Decreasing
5.0
4.5
4
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
160
VCC = 12 V
Pins 1, 2, 3 = Gnd
4.0
– 55
– 25
Figure 10. Standby Supply Current
versus Supply Voltage
7.2
5.6
– 55
Isw = 100 µA
– 25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
125
40
30
20
Pin 4 = VCC
Pins 1, 3 = Gnd
Pins 2, 5 Open
TA = +25°C
10
0
0
10
20
30
VCC, SUPPLY VOLTAGE (V)
40
MOTOROLA ANALOG IC DEVICE DATA
MC34167 MC33167
Figure 13. MC34167 Representative Block Diagram
Vin
Current
Sense
+
4
Input Voltage/VCC
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 µA
1
120
Gnd
3
Compensation
=
5
Voltage
Feedback
Input
CF
Sink Only
Positive True Logic
R2
VO
CO
RF
R1
Figure 14. Timing Diagram
4.1 V
Timing Capacitor CT
Compensation
2.3 V
ON
Switch Output
OFF
MOTOROLA ANALOG IC DEVICE DATA
5
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 13.
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.
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 6 and 14 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. Figure 9
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 3). 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
6
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 13 and 18. The equation for determining the output
voltage with the divider network is:
Vout
+ 5.05
ǒ )Ǔ
R2
R1
1
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 18) is the easiest to compensate for
stability. The step–up (Figure 20) and voltage–inverting
(Figure 22) 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 µA with a 12 V supply voltage. Figure 10
illustrates the standby supply current versus supply voltage.
The Error Amplifier output has a 100 µA current source
pull–up that can be used to implement soft–start. Figure 17
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.
Switch Output
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 18 and 22, 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 8 shows
that by clamping the emitter to 0.5 V, the collector current will
be in the range of 100 µA over temperature. A 1N5825 or
equivalent Schottky barrier rectifier is recommended to fulfill
these requirements.
Undervoltage Lockout
An Undervoltage Lockout comparator has been
incorporated to guarantee that the integrated circuit is fully
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.
MOTOROLA ANALOG IC DEVICE DATA
MC34167 MC33167
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.
DESIGN CONSIDERATIONS
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 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.
Figure 16. Over Voltage Shutdown Circuit
Figure 15. Low Power Standby Circuit
+
+
Error
Amp
100 µA
1
120
Compensation
Error
Amp
100 µA
120
Compensation
5
1
5
R1
R1
I = Standby Mode
VShutdown = VZener + 0.7
Figure 17. Soft–Start Circuit
+
Error
Amp
100 µA
120
Compensation
D2
1
5
D1
R1
Vin
1.0 M
Css
tSoft–Start ≈ 35,000 Css
MOTOROLA ANALOG IC DEVICE DATA
7
MC34167 MC33167
Figure 18. Step–Down Converter
Vin
12 V
+
4
ILIMIT
+
Oscillator
Cin
330
S
Q1
Q
R
2
PWM
D1
1N5825
UVLO
L
190 µH
Thermal
Reference
+
+
EA
R2
1
5
3
Test
Line Regulation
Load Regulation
Output Ripple
Short Circuit Current
Efficiency
CF
RF
0.1
68 k
CO
4700
6.8 k
VO
5.05 V/5.0 A
+
R1
Conditions
Results
Vin = 10 V to 36 V, IO = 5.0 A
Vin = 12 V, IO = 0.25 A to 5.0 A
4.0 mV = ± 0.039%
Vin = 12 V, IO = 5.0 A
Vin = 12 V, RL = 0.1 Ω
20 mVpp
Vin = 12 V, IO = 5.0 A
Vin = 24 V, IO = 5.0 A
78.9%
82.6%
1.0 mV = ± 0.01%
6.5 A
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 18. 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 Printed Circuit Board and Component Layout
+
8
+
R2
+
D1
Cin
R1
L
CF
RF
+
(Bottom View)
–
VO
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉ
ÉÉÉÉÉ
–
CO
Vin
1.9 ″
MC34167 STEP–DOWN
3.0″
(Top View)
MOTOROLA ANALOG IC DEVICE DATA
MC34167 MC33167
Figure 20. Step–Up/Down Converter V
in
12 V
+
4
ILIMIT
+
Oscillator
Cin
330
S
D1
1N5825
Q1
Q
R
2
PWM
L
190 µH
UVLO
*RG
620
D4
1N4148
Thermal
Q2
MTP3055EL
Reference
+
D3
1N967A
+
D2
1N5822
EA
R2
1
5
3
CF
RF
0.47
4.7 k
*Gate resistor RG, zener diode D3, and diode D4 are required only when Vin is greater than 20 V.
Test
Line Regulation
Load Regulation
Output Ripple
Short Circuit Current
Efficiency
CO
2200
6.8 k
+
VO
28 V/0.9 A
R1
1.5 k
Conditions
Results
Vin = 10 V to 24 V, IO = 0.9 A
Vin = 12 V, IO = 0.1 A to 0.9 A
10 mV = ± 0.017%
Vin = 12 V, IO = 0.9 A
Vin = 12 V, RL = 0.1 Ω
140 mVpp
Vin = 12 V, IO = 0.9 A
Vin = 24 V, IO = 0.9 A
80.1%
87.8%
30 mV = ± 0.053%
6.0 A
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 20 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.
Figure 21. Step–Up/Down Converter Printed Circuit Board and Component Layout
D3
MOTOROLA ANALOG IC DEVICE DATA
CO
D2
+
Cin
R1
D1
CF
L
R2
+
RF
+
(Bottom View)
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎ
ÎÎÎÎÎÎ
–
–
VO
ÎÎ
ÎÎ
Î
Q2
+
Vin
1.9 ″
MC34167 STEP UP-DOWN
3.45″
RG
(Top View)
9
MC34167 MC33167
Figure 22. Voltage–Inverting Converter
Vin
12 V
+
4
ILIMIT
+
Oscillator
Cin
330
S
Q1
Q
R
2
PWM
L
190 µH
UVLO
D1
1N5825
Thermal
Reference
+
+
EA
R1
1
Load Regulation
Output Ripple
Short Circuit Current
Efficiency
RF
0.47
4.7 k
VO
–12 V/1.7 A
CO
4700
+
Test
Line Regulation
CF
5
3
2.4 k
C1
R2
3.3 k
Conditions
0.047
Results
Vin = 10 V to 24 V, IO = 1.7 A
Vin = 12 V, IO = 0.1 A to 1.7 A
15 mV = ± 0.61%
Vin = 12 V, IO = 1.7 A
Vin = 12 V, RL = 0.1 Ω
78 mVpp
Vin = 12 V, IO = 1.7 A
Vin = 24 V, IO = 1.7 A
79.5%
86.2%
4.0 mV = ± 0.020%
5.7 A
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 22. 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 Printed Circuit Board and Component Layout
3.0″
+
Cin
CF
L
R2
ÎÎÎÎÎ
ÎÎÎÎÎ
ÎÎÎÎÎ
ÎÎÎÎÎ
ÎÎÎ
ÎÎÎÎÎ
ÎÎÎÎÎ
RF
+
10
–
+
D1
Vin
R1
C1
+
+
(Bottom View)
VO
–
CO
+
1.9 ″
MC34167
VOLTAGE-INVERTING
+
+
(Top View)
MOTOROLA ANALOG IC DEVICE DATA
MC34167 MC33167
Figure 24. Triple Output Converter
Vin
24 V
+
4
ILIMIT
+
Oscillator
1000
S
Q
R
2
PWM
1N5825
UVLO
MUR110
VO3
1000 –12 V/200 mA
+
Thermal
T1
Reference
+
VO2
+
1000 12 V/250 mA
MUR110
+
EA
6.8 k
1
1000
+
VO1
5.0 V/3.0 A
5
3
0.1
68 k
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 Ω
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)
ǒ
Ǔ
) VF(SEC)
+ VO(SEC)
VO(PRI))VF(PRI)
#TURNS(PRI)
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.
MOTOROLA ANALOG IC DEVICE DATA
11
MC34167 MC33167
Figure 25. Negative Input/Positive Output Regulator
+
4
ILIMIT
Oscillator
22
0.01
1N5825
S
Q1
Q
R
+
ǒ Ǔ)
5.05
R1
R2
0.7
2
UVLO
PWM
VO
L
D1
Thermal
+
R1
36 k
MTP
3055E
Reference
+
VO
+ 36 V/0.3 A
MUR415
R1
+
EA
Z1
1000
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. Variable Motor Speed Control with EMF Feedback Sensing
+
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
50 k
Faster
+
47
5
3
Test
12
0.1
Conditions
56 k
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%
MOTOROLA ANALOG IC DEVICE DATA
MC34167 MC33167
Figure 27. Off–Line Preconverter
0.001
T1
MBR20100CT
+
1000
0.001
1N5404
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
MC34167
Step–Down
Converter
+
MC34167
Step–Down
Converter
+
Output 2
0.001
3.3
+
100
1N4003
MBR20100CT
+
1000
0.001
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
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,
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 27 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
L
40
RθJA
30
0
5.0
10
15
20
25
2.5
2.0
1.5
PD, MAXIMUM POWER DISSIPATION (W)
Figure 28. D2PAK Thermal Resistance and Maximum
Power Dissipation versus P.C.B. Copper Length
1.0
30
L, LENGTH OF COPPER (mm)
MOTOROLA ANALOG IC DEVICE DATA
13
MC34167 MC33167
Table 1. Design Equations
Calculation
Step–Down
ton
toff
(Notes 1, 2)
Vin
Vout ) VF
* Vsat * Vout
Duty Cycle
(Note 3)
ton fosc
IL avg
Iout
L
Vripple(pp)
Vout
*
DIL
1
Ǔ
) (ESR)2
1
) D2IL
Vin * VsatQ1 * VsatQ2
ton
ǒ
ǒ ) Ǔ Ǹǒ Ǔ )
ǒ )Ǔ
ton
toff
DIL
1
1
2
foscCo
R
Vref 2
R1
ǒ )Ǔ
t
Iout on
toff
1
IL avg
1
1
ton fosc
ǒ )Ǔ
t
Iout on
toff
ǒ )Ǔ
R
Vref 2
R1
ǒ )Ǔ
ton
toff
ton
fosc
toff
ton fosc
DIL
1
2
8foscCo
)
*
|Vout| VF
Vin Vsat
ǒ )Ǔ
1
IL avg
Ǹǒ Ǔ
) VF2
* VsatQ2
ton
toff
ton
fosc
toff
) D2IL
Vin * Vsat * Vout
ton
ǒ
)
Voltage–Inverting
Vout VF1
Vin VsatQ1
ǒ )Ǔ
ton
toff
ton
fosc
toff
ton
Ipk(switch)
Step–Up/Down
Ǔ
(ESR)2
1
) D2IL
ǒ * Ǔ
ǒ ) Ǔ Ǹǒ Ǔ )
ǒ )Ǔ
IL avg
Vin
ton
toff
1
Vsat
ton
DIL
1
2
foscCo
R
Vref 2
R1
(ESR)2
1
NOTES: 1. Vsat – Switch Output source saturation voltage, refer to Figure 7.
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.
∆IL – 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
∆IL be chosen minimum current limit threshold of 5.5 A. If the design goal is to use a minimum inductance value, let ∆IL = 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.
14
MOTOROLA ANALOG IC DEVICE DATA
MC34167 MC33167
OUTLINE DIMENSIONS
TH SUFFIX
PLASTIC PACKAGE
CASE 314A–03
–T
–
–P
–
B
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
C
Q
E
OPTIONAL
CHAMFER
A
U
F
L
K
1 2 3 4 5
G
J 5 PL
S
D 5 PL
0.014 (0.356) M T P
M
DIM
A
B
C
D
E
F
G
J
K
L
Q
S
U
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
TV SUFFIX
PLASTIC PACKAGE
CASE 314B–05
C
B
–P
–
Q
OPTIONAL
CHAMFER
K
E
A
U
F
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.
S
L
W
V
1 2 3 4 5
G
0.24 (0.610)
J 5 PL
M T
H
D 5 PL
0.10 (0.254)
M
T P
M
N
–T
–
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
Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding
the suitability of its products for any particular purpose, nor does Motorola 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 consequential or incidental damages. “Typical” parameters which may be provided in Motorola
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. Motorola does not convey any license under its patent rights nor the rights of
others. Motorola 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 Motorola product could create a situation where personal injury
or death may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall indemnify and hold Motorola
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
Motorola was negligent regarding the design or manufacture of the part. Motorola and
are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal
Opportunity/Affirmative Action Employer.
MOTOROLA ANALOG IC DEVICE DATA
15
MC34167 MC33167
OUTLINE DIMENSIONS
T SUFFIX
PLASTIC PACKAGE
CASE 314D–03
–T
–
C
–Q
–
B
SEATING
PLANE
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.
E
U
A
DIM
A
B
C
D
E
G
H
J
K
L
Q
U
S
L
1 2 3 4 5
K
S
J
H
G
D 5 PL
0.356 (0.014)
M
T Q
INCHES
MIN
MAX
0.572 0.613
0.390 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
1.020 1.065
0.320 0.365
0.140 0.153
0.105 0.117
0.543 0.582
MILLIMETERS
MIN
MAX
14.529 15.570
9.906 10.541
4.572
4.318
0.965
0.635
1.397
1.219
1.702 BSC
2.845
2.210
0.635
0.381
25.908 27.051
9.271
8.128
3.886
3.556
2.972
2.667
13.792 14.783
M
D2T SUFFIX
PLASTIC PACKAGE
CASE 936A–02
(D2PAK)
OPTIONAL
CHAMFER
E
A
TERMINAL 6
–T
–
U
S
K
V
B
H
1
2
3
4
5
M
L
P
N
D
R
0.010 (0.254) M T
G
C
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.
DIM
A
B
C
D
E
G
H
K
L
M
N
P
R
S
U
V
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
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
How to reach us:
USA / EUROPE / Locations Not Listed: Motorola Literature Distribution;
P.O. Box 20912; Phoenix, Arizona 85036. 1–800–441–2447 or 602–303–5454
JAPAN: Nippon Motorola Ltd.; Tatsumi–SPD–JLDC, 6F Seibu–Butsuryu–Center,
3–14–2 Tatsumi Koto–Ku, Tokyo 135, Japan. 03–81–3521–8315
MFAX: [email protected] – TOUCHTONE 602–244–6609
INTERNET: http://Design–NET.com
ASIA/PACIFIC: Motorola Semiconductors H.K. Ltd.; 8B Tai Ping Industrial Park,
51 Ting Kok Road, Tai Po, N.T., Hong Kong. 852–26629298
16
◊
*MC34167/D*
MOTOROLA ANALOG IC DEVICE
DATA
MC34167/D