MC34066, MC33066
High Performance
Resonant Mode Controllers
The MC34066/MC33066 are high performance resonant mode
controllers designed for off−line and dc−to−dc converter applications
that utilize frequency modulated constant on−time or constant
off−time control. These integrated circuits feature a variable
frequency oscillator with programmable deadtime, precision
retriggerable one−shot timer, temperature compensated reference,
high gain wide−bandwidth error amplifier with a precision output
clamp, steering flip−flop, and dual high current totem pole outputs
ideally suited for driving power MOSFETs.
Also included are protective features consisting of a high speed fault
comparator and latch, programmable soft−start circuitry, input
undervoltage lockout with selectable thresholds, and reference
undervoltage lockout.
These devices are available in dual−in−line and surface mount
packages.
•
Variable Frequency Oscillator with a Control Range Exceeding
1000:1
•
Programmable Oscillator Deadtime Allows Constant Off−Time
Operation
•
Precision Retriggerable One−Shot Timer
•
Internally Trimmed Bandgap Reference
•
5.0 MHz Error Amplifier with Precision Output Clamp
•
Dual High Current Totem Pole Outputs
•
Selectable Undervoltage Lockout Thresholds with Hysteresis
•
Enable Input
•
Programmable Soft−Start Circuitry
•
Low Startup Current for Off−Line Operation
V
CC
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MARKING
DIAGRAMS
16
PDIP−16
P SUFFIX
CASE 648
1
SO−16W
DW SUFFIX
CASE 751G
1
x
A
WL
YY
WW
1
16
MC33066DW
AWLYYWW
1
= 3 or 4
= Assembly Location
= Wafer Lot
= Year
= Work Week
MC3x066P
AWLYYWW
16
16
PIN CONNECTIONS
Osc Deadtime 1
Osc RC 2
Osc Control 3
Current
Gnd 4
16 One−Shot RC
15 V
CC
14 Drive Output A
13 Drive Gnd
12 Drive Output B
11 C
Soft−Start
10 Fault Input
9
(Top View)
Enable/UVLO
Adjust
15
Enable/
UVLO Adjust 9
Osc
Deadtime
1
Osc RC
2
Osc Control
Current 3
One−Shot RC
16
V
CC
UVLO
Reference
Regulator
V
ref
UVLO
Variable
Frequency
Oscillator
Steering
Flip−Flop
One−Shot
B
out
A
out
5
4
V
ref
Gnd
V
ref
5
Error Amp Out 6
Error Amp 7
Inverting Input
Error Amp 8
Noninverting Input
Drive
14 Output A
Drive
12 Output B
13
Drive Gnd
Error Amp
Clamp
Error Amp
Out 6
Error Amp +
Error Amp −
C
Soft−Start
8
7
11
Error
Amplifier
Soft−Start
Fault−Detector/
Latch
ORDERING INFORMATION
Device
Package
PDIP−16
SO−16W
PDIP−16
Shipping
25 Units/Rail
47 Units/Rail
25 Units/Rail
10
Fault Input
MC34066P
MC33066DW
MC33066P
Figure 1. Simplified Block Diagram
©
Semiconductor Components Industries, LLC, 2006
July, 2006
−
Rev. 3
1
Publication Order Number:
MC34066/D
MC34066, MC33066
MAXIMUM RATINGS
Rating
Power Input Supply Voltage
Drive Output Current, Source or Sink (Note 1)
Continuous
Pulsed (0.5
μs,
25% Duty Cycle)
Error Amplifier, Fault, One−Shot, Oscillator, and
Soft−Start Inputs
UVLO Adjust Input
Soft−Start Discharge Current
Power Dissipation and Thermal Characteristics
DW Suffix Package, Case 751G
Maximum Power Dissipation @ T
A
= 25°C
Thermal Resistance, Junction−to−Air
P Suffix Package, Case 648
Maximum Power Dissipation @ T
A
= 25°C
Thermal Resistance, Junction−to−Air
Operating Junction Temperature
Operating Ambient Temperature
MC34066
MC33066
Storage Temperature Range
Symbol
V
CC
I
O
Value
20
0.3
1.5
−1.0
to +6.0
−1.0
to V
CC
20
V
V
mA
Unit
V
A
V
in
V
in(UVLO)
I
dchg
P
D
R
θJA
P
D
R
θJA
T
J
T
A
862
145
1.25
100
+150
0 to +70
−40
to +85
−65
to +150
mW
°C/W
W
°C/W
°C
°C
T
stg
°C
C
T
= 300 pF, C
L
= 1.0 nF, for typical values T
A
= 25°C, for min/max values T
A
is the operating ambient temperature range that applies
[Note 3], unless otherwise noted.)
Characteristics
REFERENCE SECTION
Reference Output Voltage (I
O
= 0 mA, T
A
= 25°C)
Line Regulation (V
CC
= 10 V to 18 V)
Load Regulation (I
O
= 0 mA to 10 mA)
Total Output Variation over Line, Load, and Temperature
Output Short Circuit Current
Reference Undervoltage Lockout Threshold
ERROR AMPLIFIER
Input Offset Voltage (V
CM
= 1.5 V)
Input Bias Current (V
CM
= 1.5 V)
Input Offset Current (V
CM
= 1.5 V)
Open Loop Voltage Gain (V
CM
= 1.5 V, V
O
= 2.0 V)
Gain Bandwidth Product (f = 100 kHz)
Input Common Mode Rejection Ratio (V
CM
= 1.5 V to 5.0 V)
Power Supply Rejection Ratio (V
CC
= 10 V to 18 V, f = 120 Hz)
Output Voltage Swing
High State with Respect to Pin 3 (I
Source
= 2.0 mA)
Low State with Respect to Ground (I
Sink
= 1.0 mA)
V
IO
I
IB
I
IO
A
VOL
GBW
CMRR
PSRR
V
OH
V
OL
−
−
−
70
2.5
70
80
2.3
−
1.0
0.2
0
100
4.2
95
100
2.7
0.4
10
1.0
0.5
−
−
−
−
3.1
0.6
V
ref
Reg
line
Reg
load
V
ref
I
O
V
th
5.0
−
−
4.9
25
3.8
5.1
1.0
1.0
−
100
4.3
5.2
20
20
5.3
190
4.8
Symbol
Min
Typ
Max
ELECTRICAL CHARACTERISTICS
(V
CC
= 12 V [Note 2], R
OSC
= 95.3 k, R
DT
= 0
Ω,
R
VFO
= 5.62 k, C
OSC
= 300 pF, R
T
= 14.3 k,
Unit
V
mV
mV
mV
mA
V
mV
μA
μA
dB
MHz
dB
dB
V
1. Maximum package power dissipation limits must be observed.
2. Adjust V
CC
above the Startup threshold before setting to 12 V.
3. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
T
high
= +70°C for MC34066
T
low
= 0°C for MC34066
−40°C
for MC33066
+85°C for MC33066
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MC34066, MC33066
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 12 V [Note 4], R
OSC
= 95.3 k, R
DT
= 0
Ω,
R
VFO
= 5.62 k,
C
OSC
= 300 pF, R
T
= 14.3 k, C
T
= 300 pF, C
L
= 1.0 nF, for typical values T
A
= 25°C, for min/max values T
A
is the operating ambient
temperature range that applies [Note 5], unless otherwise noted.)
Characteristics
OSCILLATOR
Frequency (Error Amp Output Low)
T
A
= 25°C
Total Variation (V
CC
= 10 V to 18 V, T
A
= T
Low
to T
High
)
Frequency (Error Amp Output High)
T
A
= 25°C
Total Variation (V
CC
= 10 V to 18 V, T
A
= T
Low
to T
High
)
Oscillator Control Input Voltage, Pin 3 (I
Sink
= 0.5 mA, T
A
= 25°C)
Output Deadtime (Error Amp Output High)
R
DT
= 0
Ω
R
DT
= 1.0 k
ONE−SHOT
Drive Output On−Time (R
DT
= 1.0 k)
T
A
= 25°C
Total Variation (V
CC
= 10 V to 18 V, T
A
= T
Low
to T
High
)
DRIVE OUTPUTS
Output Voltage
Low State (I
Sink
= 20 mA)
Low State
(I
Sink
= 200 mA)
High State (I
Source
= 20 mA)
High State
(I
Source
= 200 mA)
Output Voltage with UVLO Activated (V
CC
= 6.0 V, I
Sink
= 1.0 mA)
Output Voltage Rise Time (C
L
= 1.0 nF)
Output Voltage Fall Time (C
L
= 1.0 nF)
FAULT COMPARATOR
Input Threshold
Input Bias Current (V
Pin 10
= 0 V)
Propagation Delay to Drive Outputs (100 mV Overdrive)
SOFT−START
Capacitor Charge Current (V
Pin 11
= 2.5 V)
Capacitor Discharge Current (V
Pin 11
= 2.5 V)
UNDERVOLTAGE LOCKOUT
Startup Threshold, V
CC
Increasing
Enable/UVLO Adjust Pin Open
Enable/UVLO Adjust Pin Connected to V
CC
Minimum Operating Voltage after Turn−On
Enable/UVLO Adjust Pin Open
Enable/UVLO Adjust Pin Connected to V
CC
Enable/UVLO Adjust Shutdown Threshold Voltage
Enable/UVLO Adjust Input Current (Pin 9 = 0V)
TOTAL DEVICE
Power Supply Current (Enable/UVLO Adjust Pin Open)
Startup (V
CC
= 13.5 V)
Operating (f
OSC
= 100 kHz) (Note 4)
I
CC
mA
−
−
0.45
21
0.6
30
V
th(UVLO)
V
14.8
8.0
8.0
7.6
6.0
−
16
9.0
9.0
8.6
7.0
−0.2
17.2
10
V
10
9.6
−
−1.0
V
mA
I
chg
I
Idchg
4.5
1.0
8.1
8.0
14
−
μA
mA
V
th
I
IB
t
PLH(In/Out)
0.95
−
−
1.0
−2.0
60
1.05
−10
100
V
μA
ns
V
V
OL
V
OH
V
OL(UVLO)
t
r
t
f
−
−
9.5
9.0
−
−
−
0.8
1.5
10.3
9.8
0.8
20
20
1.2
2.0
−
−
1.2
50
50
V
ns
ns
t
OS
1.43
1.4
1.5
−
1.57
1.6
μs
f
OSC(low)
kHz
90
85
900
850
1.3
−
600
100
−
1000
−
1.4
70
700
110
115
kHz
1100
1150
1.5
100
800
V
ns
Symbol
Min
Typ
Max
Unit
f
OSC(high)
V
in
DT
V
CC(min)
V
th(Enable)
I
in(Enable)
4. Adjust V
CC
above the Startup threshold before setting to 12 V.
5. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
T
high
= +70°C for MC34066
T
low
= 0°C for MC34066
−40°C
for MC33066
+85°C for MC33066
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MC34066, MC33066
V
CC
15
50k
7k
50k
7k
+
−
8V
V
CC
UVLO
V
CC
Reference
Regulator
5.1V
UVLO
V
ref
UVLO
−
+
4.2V/4V
5
4
V
ref
Gnd
Enable/
UVLO Adjust 9
Osc Deadtime
R
DT
1
Osc RC
2
C
OSC
One−Shot RC
16
C
T
R
T
Osc Control
Current
3
I
OSC
Q1
Q2
−
+
4.9V/3.6V
One−Shot
−
+
4.9V/3.6V
UVLO + Fault
Current Mirror
Q
R
S
Fault
Fault
Latch
Fault
Comparator
Fault
10 Input
t
on
5.1V
Oscillator
Steering
Flip−Flop
Q
T
R
Q
Drivers
Drive
14 Output A
Drive
12 Output B
Drive
13 Gnd
R
OSC
I
OSC
R
VFO
+
−
2.5V
−
+
Error
Amplifier
Error Amp
Output Clamp
EA Clamp
Soft−Start
Buffer
9μA
+
−
1.0V
6
Error Amp
Output
Error Amp 7
Inverting Input
Error Amp
Noninverting Input 8
C
Soft−Start
11
Figure 2. MC34066 Representative Block Diagram
OPERATING DESCRIPTION
Introduction
As power supply designers have strived to increase power
conversion efficiency and reduce passive component size, high
frequency resonant mode power converters have emerged as
attractive alternatives to conventional square−wave control.
When compared to square−wave converters, resonant mode
control offers several benefits including lower switching
losses, higher efficiency, lower EMI emission, and smaller
size. This integrated circuit has been developed to support new
trends in power supply design. The MC34066 Resonant Mode
Controller is a high performance bipolar IC dedicated to
variable frequency power control at frequencies exceeding
1.0 MHz. This integrated circuit provides the features,
performance and flexibility for a wide variety of resonant
mode power supply applications.
The primary purpose of the control chip is to supply
precise pulses to the gates of external power MOSFETs at a
repetition rate regulated by a feedback control loop. The
MC34066 can be operated in any of three modes as follows:
1) fixed on−time, variable frequency; 2) fixed off−time,
variable frequency; and 3) combinations of 1 and 2 that
change from fixed on−time to fixed off−time as the
frequency increases. Additional features of the IC ensure
that system startup and fault conditions are administered in
a safe, controlled manner.
A simplified block diagram of the IC is shown on the first
page of this data sheet, which identifies the main functional
blocks and the block−to−block interconnects. Figure 2 is a
detailed functional diagram which accurately represents the
internal circuitry. The various functions can be divided into
two sections. The first section includes the primary control
path which produces precise output pulses at the desired
frequency Oscillator, a One−Shot, a pulse Steering
Flip−Flop, a pair of power MOSFET Drivers, and a wide
bandwidth Error Amplifier. The second section provides
several peripheral support functions including a voltage
reference, undervoltage lockout, Soft−Start circuit, and a
fault detector.
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4
MC34066, MC33066
Primary Control Path
The output pulse width and repetition rate are regulated
through the interaction of the variable frequency Oscillator,
One−Shot timer and Error Amplifier. The Oscillator triggers
the One−Shot which generates a pulse that is alternately
steered to a pair of totem−pole output drivers by a toggle
Flip−Flop. The Error Amplifier monitors the output of the
regulator and modulates the frequency of the Oscillator.
High−speed Schottky logic is used throughout the primary
control channel to minimize delays and enhance high
frequency characteristics.
Oscillator
The characteristics of the variable frequency Oscillator
are crucial for precise controller performance at high
operating frequencies. In addition to triggering the
One−Shot timer and initiating the output pulse, the
Oscillator also determines the initial voltage for the
One−Shot capacitor and defines the minimum deadtime
between output pulses. The Oscillator is designed to operate
at frequencies exceeding 1.0 MHz. The Error Amplifier can
control the oscillator frequency over a 1000:1 frequency
range, and both the minimum and maximum frequencies are
easily and accurately programmed by the proper selection of
external components. The Oscillator also includes an
adjustable deadtime feature for applications requiring
additional time between output pulses.
The functional diagram of the Oscillator and One−Shot
timer is shown in Figure 3. The oscillator capacitor C
OSC
is
initially charged by transistor Q1 through the optional
deadtime resistor R
DT
. When C
OSC
exceeds the 4.9 V upper
threshold of the oscillator comparator, the base of Q1 is
pulled low allowing C
OSC
to discharge through the external
resistors and the internal Current Mirror. When the voltage
on C
OSC
falls below the comparator’s 3.6 V lower threshold,
Q1 turns on and again charges C
OSC
.
V
CC
Osc Deadtime
1
R
DT
Osc RC
2
C
OSC
One−Shot RC
C
T
R
T
16
Osc Control
Current
3
UVLO + Fault
I
OSC
R
VFO
6
Error Amp
Output
Current Mirror
I
OSC
Q1
Q2
5.1V
Oscillator
If R
DT
is 0
Ω,
C
OSC
charges from 3.6 V to 5.1 V in less than
50 ns. The high slew rate of C
OSC
and the propagation delay
of the comparator make it difficult to control the peak
voltage. This accuracy issue is overcome by clamping the
base of Q1 through diode Q2 to a voltage reference. The
peak voltage of the oscillator waveform is thereby precisely
set at 5.1 V.
The frequency of the Oscillator is modulated by varying
the current I
OSC
flowing through R
VFO
into the Osc Control
Current pin. The control current drives a unity gain Current
Mirror which pulls an identical current from the C
OSC
capacitor. As I
OSC
increases, C
OSC
discharges faster thus
decreasing the Oscillator period and increasing the
frequency. The maximum frequency occurs when the Error
Amplifier output is at the upper clamp level, nominally
2.5 V above the voltage at the Osc Control Current pin. The
minimum discharge time for C
OSC
, which corresponds to
the maximum oscillator frequency, is given by Equation 1.
2.5ROSC + 5.1
RVFO
2.5ROSC + 3.6
RVFO
t
dchg(min)
= (R
DT
+ R
OSC
)C
OSC
In
(1)
The minimum oscillator frequency will result when the
I
OSC
current is zero, and C
OSC
is discharged through the
external resistors R
OSC
and R
DT
. This occurs when the Error
Amplifier output voltage is less than the two diode drops
required to bias the input of the Current Mirror. The
maximum oscillator discharge time is given by Equation 2.
t
dchg(max)
= (R
DT
+ R
OSC
) C
OSC
In
5.1
3.6
(2)
R
OSC
−
+
4.9V/3.6V
One−Shot
The outputs of the control IC are off whenever the
oscillator capacitor C
OSC
is being charged by transistor Q1.
The minimum time between output pulses (deadtime) can be
programmed by controlling the charge time of C
OSC
.
Resistor R
DT
reduces the current delivered by Q1 to C
OSC
,
thus increasing the charge time and output deadtime.
Varying R
DT
from 0
Ω
to 1000
Ω
will increase the output
deadtime from 80 ns to 680 ns with C
OSC
equal to 300 pF.
The general expression for the oscillator charge time is give
by Equation 3.
t
chg(max)
= R
DT
C
OSC
In
5.1−3.6
+ 80 ns
5.1−4.9
(3)
−
+
4.9V/3.6V
The minimum and maximum oscillator frequencies are
programmed by the proper selection of resistor R
OSC
and
R
VFO
. After selecting R
DT
for the desired deadtime, the
minimum frequency is programmed by R
OSC
using
Equations 2 and 3 in Equation 4:
1
= t
dchg(max)
+ t
chg
f
OSC(min)
(4)
Figure 3. Oscillator and One−Shot Timer
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