HA17384SPS/SRP, HA17384HPS/HRP,
HA17385HPS/HRP
High Speed Current Mode PWM Control IC
for Switching Power Supply
ADE-204-028A (Z)
2nd Edition
Nov. 1999
Description
The HA17384S/H and HA17385H are PWM control switching regulator IC series suitable for highspeed,
current-mode switching power supplies. With ICs from this series and a few external parts, a small, low
cost flyback-transformer switching power supply can be constructed, which facilitates good line regulation
by current mode control. Synchronous operation driven after an external signal can also be easily obtained
which offers various applications such as a power supply for monitors small multi-output power supply.
The IC series are composed of circuits required for a switching regulator IC. That is a under-voltage
lockout (UVL), a high precision reference voltage regulator (5.0 V ± 2%), a triangular wave oscillator for
timing generation, a high-gain error amplifier, and as totem pole output driver circuit which directly drives
the gate of power MOSFETs found in main switching devices. In addition, a pulse-by-pulse type, highspeed, current-detection comparator circuit with variable detection level is incorporated which is required
for current mode control.
The HA17384SPS includes the above basic function circuits. In addition to these basic functions, the H
Series incorporates thermal shut-down protection (TSD) and overvoltage protection (OVP) functions, for
configuration of switching power supplies that meet the demand for high safety levels.
Between the HA17384 and HA17385, only the UVL threshold voltages differ as shown in the product
lineup table.(See next page.)
This IC is pin compatible with the “3842 family” ICs made by other companies in the electronics industry.
However, due to the characteristics of linear ICs, it is not possible to achieve ICs that offer full
compatibility in every detail.
Therefore, when using one of these ICs to replace another manufacturer’s IC, it must be recognized that it
has different electrical characteristics, and it is necessary to confirm that there is no problem with the power
supply (mounting) set used.
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Functions
• Under-voltage lockout system
• Reference voltage regulator of 5.0 V ± 2%
• Triangular wave (sawtooth) oscillator
• Error amplifier
• Totem pole output driver circuit (direct driving for power MOSFETs)
• Current-detection comparator circuit for current mode
• OVP function (over voltage protection) *1
• TSD function (thermal shut-down protection) * 1
• Protect function by zener diode (between power input and GND)
Note: 1. H series only.
Features
• High-safety UVL circuit is used (Both VIN and Vref are monitored)
• High speed operation:
Current detection response time: 100 ns Typ
Maximum oscillation frequency: 500 kHz
• Low standby current: 170 µA Typ
• Wide range dead band time
(Discharge current of timing capacitance is constant 8.4 mA Typ)
• Able to drive power MOSFET directly
(Absolute maximum rating of output current is ±1 A peak)
• OVP function (over voltage protection) is included *1
(Output stops when FB terminal voltage is 7.0 V Typ or higher)
• TSD function (thermal shut-down protection) is included *1
(Output stops when the temperature is 160°C Typ or higher)
• Zener protection is included
(Clamp voltage between VIN and GND is 34 V Typ)
• Wide operating temperature range:
Operating temperature: –20°C to +105°C
Junction temperature: 150°C * 2
Note: 1. H series only.
2. S series only.
2
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Product Line-up
UVL Power Supply
Threshold Voltage
Package
Additional Function
DILP8 (DP-8)
SOP8 (FP-8DC)
TSD
(Thermal shutdown protection)
OVP
(Over voltage
protection)
VTH UVL (V) Typ
VTL UVL (V) Typ
HA17384SPS
HA17384SRP
—
—
16.0
10.0
HA17384HPS
HA17384HRP
❍
❍
HA17385HPS
HA17385HRP
❍
❍
8.4
7.6
Pin Arrangement
COMP
1
8
Vref
FB
2
7
VIN
CS
3
6
OUT
RT/CT
4
5
GND
(Top view)
Pin Function
Pin No.
Symbol
Function
1
COMP
Error amplifier output pin
2
FB
Inverting input of error amp./OVP input pin
3
CS
Current sensing signal input pin
4
RT/CT
Timing resistance, timing capacitance connect pin
5
GND
Groung pin
6
OUT
PWM Pulse output pin
7
VIN
Power supply voltage input pin
8
Vref
Reference voltage 5V output pin
Note:
Note
1
1. Overvoltage protection (OVP) input is usable only for the HA17384H and HA17385H.
3
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Block Diagram
0.8mA
UVL1
COMP
1
L
−
+
EA
OVP
latch
R Q
−
OVP
+ *1
2
7.0V
VL VH
8
Vref
7
VIN
6
OUT
5
GND
UVL2
6.5V
1
2 Vref
(2.5V)
FB
(OVP input)
5V band
gap
reference
regulator
H
Vref > 4.7V
S
2VF
TSD
sense
OR
34V
2R
R
160°C
1V
CS
latch
−
CS
3
+
NOR
R
CS
Q
S
OUT
PWM LOGIC
Totem pole
output circuit
Vref
Oscillator
+
RT/CT
−
4
2.8 V
Latch set
pulse
1.2V
8.4 mA
Note: 1. Blocks with bold line are not included in HA17384SPS/SRP.
4
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Absolute Maximum Ratings
Item
Symbol
Rating
Unit
Supply voltage
VIN
30
V
DC output current
IO
±0.1
A
Peak output current
I O PEAK
±1.0
A
Error amplifier input voltage
VFB
–0.3 to VIN
V
COMP terminal input voltage
VCOMP
–0.3 to +7.5
V
Error output sink current
I OEA
10
mA
Power dissipation
PT
680
mW
Operating temperature
Topr
–20 to +105
°C
Junction temperature
Tj
125
°C
3
150
°C
4
–55 to +125
°C
3
–55 to +150
°C
4
Storage temperature
Tstg
Note
1, 2
Notes: 1. For the HA17384HPS and HA17385HPS,
This value applies up to Ta = 43°C; at temperatures above this, 8.3 mW/°C derating should be
applied.
For the HA17384SPS,
This value applies up to Ta = 68°C; at temperatures above this, 8.3 mW/°C derating should be
applied.
Power Dissipation PT (mW)
800
680mW
HA17384SPS
600
HA17384HPS, HA17385HPS
400
374mW
200
166mW
43°C
0
−20
0
20
68°C
40
60
80
100
Ambient Temperature Ta (°C)
105°C
120
125°C
140
150°C
160
5
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Absolute Maximum Ratings (cont)
Notes: 2. This is the value when the device is mou nted on a glass-epoxy substrate (40 mm × 40 mm × 1.6
mm). However,
For the HA17384HRP and HA17385HRP,
Derating should be performed with 8.3 mW/°C in the Ta ≥ 43°C range if the substrate wiring
density is 10%.
Derating should be performed with 11.1 mW/°C in the Ta ≥ 63°C range if the substrate wiring
density is 30%.
For the HA17384SRP,
Derating should be performed with 8.3 mW/°C in the Ta ≥ 68°C range if the substrate wiring
density is 10%.
Derating should be performed with 11.1 mW/°C in the Ta ≥ 89°C range if the substrate wiring
density is 10%.
HA17384SRP
: −11.1 mW/°C (wiring density is 30%)
: −8.3 mW/°C (wiring density is 10%)
HA17384HRP, HA17385HRP
: −11.1 mW/°C (wiring density is 30%)
: −8.3 mW/°C (wiring density is 10%)
Power Dissipation PT (mW)
800
680 mW
600
500 mW
374 mW
400
222 mW
200
166 mW
0
−20
0
43°C
20
63°C
68°C
89°C
40
60
80
100
Ambient Temperature Ta (°C)
3. Applies to the HA17384HPS/HRP and HA17385HPS/HRP.
4. Applies to the HA17384SPS/SRP.
6
105°C
120
125°C
140
150°C
160
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Electrical Characteristics
(The condition is: Ta = 25°C, VIN = 15 V, CT = 3300 pF, RT = 10 kΩ without notice)
Reference Part
Item
Symbol
Min
Typ
Max
Unit
Test Condition
Note
Reference output voltage
Vref
4.9
5.0
5.1
V
Io = 1 mA
Line regulation
Regline
—
20
50
mV
12 V ≤ VIN ≤ 25 V
Load regulation
Regload
—
10
25
mV
–1 mA ≥ Io ≥ –20 mA
Output short current
los
–30
–100
–180
mA
Vref = 0V
Temperature stability
∆Vref
—
80
—
ppm/°C
Io = –1 mA,
–20°C ≤ Ta ≤ 105°C
1
Output noise voltage
VN
—
100
—
µV
10 Hz ≤ fnoise ≤ 10 kHz
1
Notes: 1. Reference value for design.
Triangular Wave Oscillator Part
Item
Symbol
Min
Typ
Max
Unit
Test Condition
Typical oscillating frequency
fosc Typ
47
52
57
kHz
CT = 3300 pF,
RT = 10 kΩ
Maximum oscillating
frequency
fosc Max
500
—
—
kHz
Supply voltage dependency of
oscillating frequency
∆fosc 1
—
±0.5
±2.0
%
12 V ≤ V IN ≤ 25 V
Temperature dependency of
oscillating frequency
∆fosc 2
—
±5.0
—
%
–20°C ≤ Ta ≤ 105°C
Discharge current of CT
Isink CT
7.5
8.4
9.3
mA
VCT = 2.0 V
Low level threshold voltage
VTLCT
—
1.2
—
V
1
High level threshold voltage
VTHCT
—
2.8
—
V
1
Triangular wave amplitude
∆VCT
—
1.6
—
V
∆VCT = VTHCT – VTLCT
Note
1
1
Notes: 1. Reference value for design.
7
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Electrical Characteristics (cont)
Error Amplifire Part / OVP Part
Item
Symbol
Min
Typ
Max
Unit
Test Condition
Non-inverting input voltage
VFB
2.42
2.50
2.58
V
VCOMP = 2.5 V
Input bias current
I IB
—
–0.2
–2.0
µA
VFB = 5.0 V
Open loop voltage gain
AVOL
65
90
—
dB
2.0 V ≤ V O ≤ 4.0 V
Unity gain bank width
BW
0.7
1.0
—
MHz
Power supply voltage
rejection ratio
PSRR
60
70
—
dB
12 V ≤ V IN ≤ 25 V
Output sink current
I Osink EA
3.0
9.0
—
mA
VFB = 2.7 V, VCOMP = 1.1 V
Output source current
I Osource EA
–0.5
–0.8
—
mA
VFB = 2.3 V, VCOMP = 5.0 V
High level output voltage
VOH EA
5.5
6.5
7.5
V
VFB = 2.3 V,
RL = 15 kΩ(GND)
Low level output voltage
VOL EA
—
0.7
1.1
V
VFB = 2.7 V,
RL = 15 kΩ(Vref)
OVP latch threshold
voltage
VOVP
6.0
7.0
8.0
V
Increase FB terminal
voltage
1
OVP (FB) terminal input
current
I FB(OVP)
—
30
50
µA
VFB = 8.0 V
1
OVP latch reset V IN voltage
VIN(OVP RES)
6.0
7.0
8.0
V
Decreasing VIN after OVP
latched
1
Note:
8
Note
1. These values are not prescribe to the HA17384SPS/SRP because OVP function is not included.
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Electrical Characteristics (cont)
Current Sensing Part
Item
Symbol
Min
Typ
Max
Unit
Test Condition
Note
Voltage gain
AVCS
2.85
3.00
3.15
V/V
VFB = 0 V
1
Maximum sensing voltage
Vth CS
0.9
1.0
1.1
V
Power supply voltage
rejection ratio
PSRR
—
70
—
dB
12 V ≤ V IN ≤ 25 V
2
Input bias current
I BCS
—
–2
–10
µA
VCS = 2 V
Current sensing
response time
tpd
50
100
150
ns
Time from when VCS
becomes 2 V to when
output becomes “L” (2 V)
3
Notes: 1. The gain this case is the ratio of error amplifier output change to the current-sensing threshold
voltage change.
2. Reference value for design.
3. Current sensing response time tpd is definded a shown in the figure 1.
Vth
VCS
VOUT
(PWM)
tpd
Figure 1 Definition of Current Sensing Response Time tpd
PWM Output Part
Item
Symbol
Min
Typ
Max
Unit
Test Condition
Output low voltage 1
VOL1
—
0.7
1.5
V
losink = 20 mA
Output low voltage 2
VOL2
—
1.5
2.2
V
losink = 200 mA
Output high voltage 1
VOH1
13.0
13.5
—
V
losource = –20 mA
Output high voltage 2
VOH2
12.0
13.3
—
V
losource = –200 mA
Output low voltage at
standby mode
VOL STB
—
0.8
1.1
V
VIN = 5 V,
losink = 1 mA
Rise time
tr
—
80
150
ns
CL = 1000 pF
Fall time
tf
—
70
130
ns
CL = 1000 pF
Maximum ON duty
Du max
94
96
100
%
Minimum ON duty
Du min
—
—
0
%
Note
1
1
Notes: 1. Pulse application test
9
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Electrical Characteristics (cont)
UVL Part
Item
Symbol
Min
Typ
Max
Unit
Test Condition
Note
Threshold voltage for
VTH UVL
14.5
16.0
17.5
V
Turn-ON voltage
1
7.6
8.4
9.2
V
when VIN is rising
2
9.0
10.0
11.0
V
Minimum operating
1
6.8
7.6
8.4
V
voltage after turn-ON
2
5.0
6.0
7.0
V
VHYS UVL = VTH UVL – VTL UVL
1
0.6
0.8
1.0
V
4.3
4.7
Vref
V
high V IN level
Threshold voltage for
VTL UVL
low VIN level
VIN UVL hysteresis voltage
Vref UVL threshold voltage
VHYS UVL
VT Vref
2
Voltage is forced toVref
terminal
Notes: 1. For the HA17384S/H.
2. For the HA17385H.
Total Characteristics
Item
Symbol
Min
Typ
Max
Unit
Test Condition
Operating current
I IN
7.0
10.0
13.0
mA
CL = 1000 pF, VFB = VCS = 0 V
Standby current
I STBY
120
170
230
µA
Current at start up
Current of latch
I LATCH
200
270
340
µA
VFB = 0 V after VFB = VOVP
Power supply zener
voltage
VINZ
31
34
37
V
I IN + 2.5 mA
Overheat protection
starting temperature
TjTSD
—
160
—
°C
Notes: 1.
2.
2.
4.
10
Note
1, 2
3, 4
These values are not prescribe to the HA17384SPS/SRP because OVP function is not included.
VIN = 8.5 V in case of the HA17384H.
These values are not prescribe to the HA17384SPS/SRP because TSD function is not included.
Reference value for design.
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Timing Chart
Signal Name
Waveform timing (Outline)
Power ON
IC turn ON
OVP input
Stationary operation
Input voltage
VIN Pin 7
2V
16 V
(8.4 V)
UVL1
Internal signal which
cannot be externally
monitored.
OVP latched
condition
This voltage is determined
by the transformer
0V
Power OFF
Reset of
OVP latch
10 V
(7.6 V)
7.0 V
2V
( ) shows the case
using HA17385H
0V
5V
Reference voltage
Vref Pin 8
0V
UVL2
Internal signal which
cannot be externally
monitored.
0V
Oscillation voltage of
triangular wave
RT/CT Pin 4
Start up signal
Internal signal which
cannot be externally
monitored.
PWM latch setting signal
internal signal which
cannot be externally
monitored.
4.7 V
4.7 V
2.8 V
1.2 V
0V
IC operates and
PWM output stops.
0V
Start up latch
release
0V
7.0 V typ
(OVP input)
Error amplifier input signal
VFB Pin 2
0V
VCOMP
Error amplifier output signal
0V
VCOMP Pin 1
ID *1
OVP latch signal
Internal signal which
cannot be externally
monitored.
PWM output voltage
VOUT Pin 6
ID
0V
VIN
0V
Note: 1. ID indicates the power MOSFET drain current; it is actually observed as voltage VS generated
by power MOSFET current detection source resistance RS.
VCOMP indicates the error amp output voltage waveform. Current mode operation is
performed so that a voltage 1/3 that of VCOMP is the current limiter level.
11
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Operation (Description of Timing Chart)
From Power ON to Turn On
After the power is switched ON, the power supply terminal voltage (VIN) of this IC rises by charging
through bleeder resistor RB. At this time, when the power voltage is in the range of 2 V to 16 V*1 . The
low-voltage, lock out UVL1 operates and accordingly the OUT voltage, that is, the gate voltage of the
power MOSFET, is fixed at 1.3 V or a lower value, resulting in the power MOSFET remaining in the OFF
state.
When the power supply voltage reaches 16 V, UVL1 of this IC is reset and the reference voltage (Vref)
generating part turns ON. However, until Vref becomes 4.7 V, the low-voltage, lock out UVL2 operates to
keep the OUT terminal voltage low. After Vref terminal voltage becomes 4.7 V or higher, OUT terminal
outputs a PWM pulse.
Note: 1. The value is for the HA17384S/H.
The value is 8.4 V for the HA17385H.
Generation of Triangular Wave and PWM Pulse
After the output of the Vref, each blocks begins to operate. The triangular wave is generated on the RT/CT
terminal. For PWM pulses, the triangular wave rise time is taken as the variable on-duty on-time. The
triangular wave fall time is taken as the dead-band time. The initial rise of the triangular wave starts from 0
V, and to prevent a large on-duty at this time, the initial PWM pulse is masked and not output. PWM
pulses are outputted after the second triangular wave. The above operation is enabled by the charge energy
which is charged through the bleeder resistor RB into the capacitor CB of VIN.
Stationary Operation
PWM pulses are outputted after the second wave of the triangular wave and stationary operation as the
switching power supply starts.
By switching operation from ON/OFF to OFF/ON in the switching device (power MOSFET), the
transformer converts the voltage. The power supply of IC VIN is fed by the back-up winding of the
transformer.
In the current mode of the IC, the current in the switcing device is always monitored by a source resistor
R CS. Then the current limiter level is varied according to the error voltage (COMP terminal voltage) for
PWM control. One third of the error voltage level, which is divided by resistors “2R” and “R” in the IC, is
used to sense the current (R = 25 kΩ).
Two diodes between the error output and the 2R-R circuit act only as a DC level shifter. Actually, these
diodes are connected between the 2R-R circuit and GND, and, the current sensing comparator and GND,
respectively. Therefore, these blocks operate 1.4 V higher than the GND level. Accordingly, the error of the
current sensing level caused by the switching noise on the GND voltage level is eliminated. The zener
diode of 1 V symbolically indicates that the maximum sensing voltage level of the CS terminal is 1 V.
12
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Power OFF
At power OFF, the input voltage of the transformer gradually decreases and then VIN of IC also decreases
according to the input voltage. When V IN becomes lower than 10 V*2 or Vref becomes lower than 4.7 V,
UVL1 (UVL2) operates again and the PWM pulse stops.
Note: 2. The value is for the HA17384S/H.
The value is 7.6 V for the HA17385H.
Commercial AC voltage
+
−
100µ
200V
−
Power switch
+
Rectifier
bridge diode
Line filter
CB
10µ
50V
3.6k
OVP input
(Ex: from photocoupler)
SBD
ex. HRP24
+
HRP32
P
VIN
20k
RB
220k
1/4W
+
−
S
B
150k
DC
output
1000µ
10V
0.1µ
COMP
+
−
−
Floating
ground
Vref
100p
FB
VIN
CS
OUT
51
RT
10k
RT/CT
CT
3300p
Power MOSFET
ex. 2SK1567
GND
HA17384H,
HA17385H
VCS
330p
1k
RCS
1
2W
Figure 2 Mounting Circut Diagram for Operation Expression
13
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
2R
2VF
R
1V
CS
latch
−
VCS
CS terminal
+
VCOMP
COMP terminal
(Error output)
R
CS
S
Q
PWM pulse
Latch setting pulse
(Implemented in triagular
wave oscillator)
Latch setting
pulse
VCOMP
Error voltage
× 1 3
VCS
Current sensing
level
Current Sense Comparator
Threshold Voltage VCS (V)
Figure 3 Operation Diagram of Current Sensing Part
Point: 1) At maximum rated load, the setting should be made to give
approximately 90% of area A below.
2) When the OVP latch is operated, the setting should be made
in area B or C.
1.0
B
Heavy load
0.8
A : Stationary operation / PWM
(Current-mode operation)
B : Current limit operation / Max duty cycle
C : No sensitivity area / No PWM output
0.6
A
0.4
Light load
1.4V
0.2
4.4V
7.5V
C
0.0
0
1
2
3
4
5
6
7
Error Amplifier Output Voltage Vcomp (V)
Figure 4 Current Sense Characteristics
14
8
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Features and Theory of Current Mode Control
Features of Current Mode Control
• Switch element current detection is performed every cycle, giving a high feedback response speed.
• Operation with a constant transformer winding current gives a highly stable output voltage (with
excellent line regulation characteristics, in particular).
• Suitable for flyback transformer use.
• External synchronous operation is easily achieved. (This feature, for example, is applicable to
synchronization with a forizontal synchronizing signal of CRT monitor.)
Theory of Current Mode Control
In current mode control, a PWM pulse is generated not by comparing an error voltage with a triangular
wave voltage in the voltage mode, but by changing the current limiter level in accordance with the error
voltage (COMP terminal in this IC, that is,output of the error amplifier output) which is obtained by
constantly monitoring the current of the switching device (power MOSFET) using source resistor R CS.
One of the features of current mode control is that the current limited operates in all cycles of PWM as
described by the above theory.
In voltage mode, only one feedback loop is made by an output voltage. In current mode, on the other hand,
two loops are used. One is an output voltage loop and the other is a loop of the switching device current
itself. The current of the switching device can be controlled switch high speed. In current mode control,
the current in the transformer winding is kept constant, resulting in high stability. An important
consequence is that the line regulation in terms of total characteristics is better than that in voltage mode.
Transformar
AC
input
DC
output
OSC
S
RS
Flip flop
R
Current sense
comparator
+
−
IS
2R
R
−
VCOMP +
Error amplifier
Vref
Figure 5 Block Diagram of Current Mode Switching Power Spply
15
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
A. Control in the case of heavy load
VCS
IS
B. Control in the case of light load
VCS
IS
As the load becomes heavy and the DC output decreases, the current sensing
level is raised as shown in A. above in order to increase the current in the switching
device in each cycle. When the load decreases, inverse control is carried out as
shown in B. above.
Figure 6 Primary Current Control of Transformer in Current Mode (Conceptual Diagram)
16
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Main Characteristics
Supply Current vs. Supply Voltage (HA17384S/H)
Supply Current vs. Supply Voltage (HA17385H)
20
Ta = 25°C
fosc = 52kHz
CT = 3300pF
RT = 10kΩ
Operating Current IIN (mA)
Operating Current IIN (mA)
20
15
10
Latch current
(HA17384H)
5
0
0
10
20
30
Power supply voltage VIN (V)
CT = 3300pF
RT = 10kΩ
15
10
5
0
40
Ta = 25°C
fosc = 52kHz
Latch current
0
10
20
30
Power supply voltage VIN (V)
40
Standby Current/Latch Current vs. Supply Voltage
Standby Current/Latch Current vs. Supply Voltage
Exploded diagram of the small current part from the above figure
(HA17384S/H)
Exploded diagram of the small current part from the above figure
(HA17385H)
1.5
1.0
Latch current
(HA17384H)
0.5
0
2.0
Ta = 25°C
Operating Current IIN (mA)
Operating Current IIN (mA)
2.0
0
10
20
30
Power supply voltage VIN (V)
1.5
1.0
Latch current
0.5
0
40
Ta = 25°C
0
10
20
30
Power supply voltage VIN (V)
40
Operating Current vs. Ambient Temperature Standby Current/Latch Current vs. Ambient Temperature
400
VIN = 15V
fosc = 52kHz
CT = 3300pF
RT = 10kΩ
Standby ⋅ Latch Current (µA)
Operating Current IIN (mA)
12
11
10
9
8
−20
0
20
40
60
80
Ambient temperature Ta (°C)
105
300
Latch current
VIN = 15V (HA17384H)
VIN = 8.5V (HA17385H)
200
100
0
−20
Stanby current
0
20
40
60
80
Ambient temperature Ta (°C)
105
17
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
UVL Threshold Voltage vs. Ambient Temperature
20
Line Regulation Characteristics of Reference Voltage
5.2
15
VTH
Reference voltage Vref (V)
UVL voltage (V)
HA17384S/H
HA17385H
VTL
10
VTH
VTL
5
0
−20
5.0
Vref short
protection
operates
4.5
CT discharge current ICT (mA)
Ta = 25°C
VIN = 15V
Measured when
RT/CT terminal voltage
is externally supplied
Minimum voltage of
triangular wave
Maximum voltage of
triangular wave
7.5
0
18
1
2
3
RT/CT terminal voltage VCT (V)
4
10
20
Supply voltage VIN (V)
30
Reference Voltage vs. Ambient Temperature
5.2
VIN = 15V
CT = 3300pF
RT = 10kΩ
5.1
5.0
4.9
4.8
−20
20
40
60
80
100
Output current of Vref terminal (mA)
CT Discharge Current vs. RT/CT Terminal Voltage
9.5
8.0
4.9
0
Reference voltage Vref (V)
CT = 3300pF
RT = 10kΩ
5.5
8.5
5.0
85
CT discharge current IsinkCT (mA)
Reference voltage Vref (V)
Ta = 25°C
VIN = 15V
9.0
5.1
4.8
0
20
40
60
Ambient temperature Ta (°C)
Load Regulation Characteristics of Reference Voltage
6.0
4.0
0
Ta = 25°C
CT = 3300pF
VIN = 10V or more (HA17384S/H) RT = 10kΩ
VIN = 7.6V or more (HA17385H)
0
20
40
60
80
Ambient temperature Ta (°C)
105
CT Discharge Current vs. Ambient Temperature
9.5
VIN=15 V
9.0
Measured when RT/CT
terminal voltage of 2 V is
externally supplied
8.5
8.0
7.5
−20
0
20
40
60
80
Ambient temperature Ta (°C)
105
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Ta = 25¡C
VIN = 15V
200
F
0p
47
=
pF
CT
00
F
10 00p F
22 00p
µF
47
01
0.
µF
2
02
F
0.
7µ
04
0.
Oscillation frequency fosc (kHz)
500
100
50
20
10
5
500
1k
2k
5k
10k 20k
50k 100k 200k
Timing resistance RT (Ω)
Figure 7 Oscillation Frequency vs. Timing Resistance
Case 1.
Setting large maximum duty cycle.
Triangular wave
PWM maximum ON pulse
Du max = 95%
fosc = 52kHz
In the case of small CT and large RT
(ex. CT = 3300pF, RT = 10kΩ)
Case 2.
Setting small maximum duty cycle.
Triangular wave
PWM maximum ON pulse
Du max = 40%
fosc = 52kHz
In the case of large CT and small RT
(ex. CT = 0.033µF, RT = 680Ω)
Figure 8 Relationship Between Triangular Wave and Maximum ON Duty of PWM Pulse
19
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Maximum ON duty Du max (%)
100
Ta = 25°C
VIN = 15V
75
50
25
0
500
1k
2k
5k
10k
20k
50k
100k 200k
Timing Resistance RT (Ω)
Note: In the oscillation system of this IC, a constant discharging current of 8.4mA
flows the timing capacitor during triangular wave fall. Therefore, note that a
small maximum ON duty (large dead band) leads to a large supply current.
Refer to the equations of oscillation frequency and supply current for details.
Figure 9 PWM Pulse ON Duty vs. Timing Resistance
20
VIN = 15V
CL = 1000pF
60
C = 3300pF
Dumax = 95% RT = 10kΩ
T
55
50
C = 0.033µF
Dumax = 40% RT = 680Ω
T
45
40
−20
0
20
40
60
80
Ambient Temperature Ta (°C)
Rise/Fall Time (ns)
Ta = 25°C
CT = 3300pF
RT = 10kΩ
150
e tr
tim
Rise
100
me
ll Ti
tf
Fa
50
0
0
1000
2000
3000
4000
Output load capacitance CL (pF)
Current sensing level VCS (V)
Current Sensing Level vs. Ambient Temperature
1.25
1.00
VIN = 15V Measured when COMP terminal
VFB = 0V voltage is externally supplied
0.75
0.50
CL = 1000pF
20
VCS = 0V
VFB = 0V
fos
c=3
00
15
kH
z
fos
c=5
0kH
10
z
5
25
50
75
100
Maximum ON Duty Du max (%)
Rise/Fall Time of Output Pulse vs. Ambient Temperature
250
VIN = 15V
VCS = 0V
200 VFB = 0V
CL = 1000pF
CT = 3300pF
RT = 10kΩ
150
Rise time tr
100
Fall Time tf
50
0
−20
0
20
40
60
80
Ambient temperature Ta (°C)
105
Relationship Between Low Voltage Malfunction
Protection and PWM Output
VIN
(UVL1)
L
H
H
L
Vref
(UVL2)
L
L
H
H
PWM
OUTPUT
L
L
Available
to
output
L
IC is in
the ON
Condition Standby state and Operation Standby
state
description state
output is state
fixed to
LO.
0.25
0
−20
Operating Current vs. Maximum ON Duty
25
VIN = 15V
Ta=25°C
0
0
105
Rise/Fall Time of Output Pulse vs. Load Capacitance
250
VIN = 15V
VCS = 0V
200 VFB = 0V
Operating Current IIN (mA)
Oscillation Frequency vs. Ambient Temperature
65
Rise/Fall Time (ns)
Oscillation Frequency fosc (kHz)
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
0
20
40
60
80
Ambient temperature Ta (°C)
105
21
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
100
VIN = 15V, Ta = 25°C
50
Gain AVO
25
Unit gain frequency
fT = 1MHz Typ
60
0
Phase Φ
Phase margin
at fT
ΦO = 60° Typ
−25
10
0
100
1k
10k
100k
1M
120
180
10M
Error Amplifier Input Signal Frequency f (Hz)
Figure 10 Open Loop Gain Characterisrics of Error Amplifier
22
Phase Φ (deg)
Gain AVO (dB)
75
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
•Calculation of operation parameters
1. Maximum ON duty Du max (Refer to the right figure.)
1
Du max =
190Ω
1 + 1.78 × In 1 +
RT − 440Ω
Triangular wave
2. Oscillation frequency fosc
PWM maximum
ON pulse
(
)
1
fosc =
CT × RT ×
{ 0.56 + In (1 + R 190Ω
− 440Ω )}
T
From the above two equations, the following two equations are
obtained.
3. Equalization to device RT from Du max
RT =
e
190Ω
0.56 (1/Du max − 1)
+ 440Ω
−1
(e = 2.71828.base of natural logarithm)
4. Equation to device CT from fosc and RT
Du max
CT = 1.78 ×
fosc × RT
Dumax is the ratio of
maximum ON time of
PWM to one cycle time.
In the above case,
Dumax = 95%
5. Operating current IIN
IIN = IQ + IsinkCT × (1 − Du max) + Ciss × VIN × fosc
providing that IQ = 8.4mA Typ (Supply current when oscillation in IC stops.)
Ciss is the input gate capacitance of the power MOSFET which is connected and VIN is
the supply voltage of the IC.
Example 1: Calculation when RT = 10kΩ and CT = 3300pF
fosc = 52kHz, Du max = 95%, IIN = 9.7mA
Example 2: Calculation for 50% of Du max and 200 kHz of fosc
RT = 693Ω, CT = 6360pF, IIN = 12.5mA
However, Ciss = 1000pF, VIN = 18V
Note that the actual value may differ from the calculated one because of the internal
delay in operation and input characteristics of the POWER MOS FET. Check the
value when mounting.
Additionally a small Dumax leads to a large supply current, even if the frequency is
not changed, and start up may become difficult. In such a case, the following
measure is recommended.
(1) For an AC/DC converter, a small bleeder resistance is required.
(2) The large capacitance between Vref and GND is required.
(3) Use a large Dumax with a triangular wave and raise the current limit of the
switching device to around the maximum value (1.0V Typ).
V
The current limit is expressed as IDmax = THCS
RCS
Figure 11 Calculation of Operation Parameters
23
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Application Circuit Example (1)
Rectifier bridge diode
+
141V
−
+
−
Commercial
AC 100V
Line filter
100µ
200V
16.4V
VIN
20k
220k
1/4W
SBD
1000µ
HRP24
10V
+
HRP32
P
10µ
50V
+
−
S
B
HA17384H,
HA17385H
2SA1029
0.1µ
COMP
150k
10k
100p
VIN
CS
OUT
51
RT
10k
47k
Vref
FB
RT/CT
HA17431
CT
3300p
470p
1k
DC 5V, 3A
OUTPUT
−
3.6k
10k
+
−
GND
1k
Transformer specification
example
EI-22 type core
(H7C18 × 06Z)
Gap length
lg = 0.3mm
2SK1567
Transformer coil example
P: 0.5¿80T/570µH
S: 0.5¿16T Bifiler/22µH
B: 0.2¿44T/170µH
1
2W
Notes: 1.
: PRIMARY GND, : SECONDARY GND.
2. Check the wiring direction of the transformer coil.
3. Insert a snubber circuit if necessary.
4. OVP function is not included in HA17384SPS/SRP.
Snubber circuit
example
470p
1kV
FRD
DFG1C8
51
P
S
(Opetation Theory)
Because this circuit is a flyback type, the voltages in the
primary (P), secondary (s) coils of the transformer and
backup (B) coil are proportional to each other. Using this,
the output voltage of the backup coil (VIN of IC) is controlled
at constant 16.4V. (The voltage of the point divided by
resistors of 20kΩ and 3.6kΩ is 2.5V).
Figure 12 Primary Voltage Sensing Flyback Converter
24
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Application Circuit Example (2)
When the error amplifier is used
−
Rectifier bridge diode
+
141V
+
−
Commercial
AC 100V
100µ
200V
220k
1/4W
Line filter
2SA1029
10k
HRP32
VIN
16.4V
10k
P
10µ
50V
47k
SBD
HRP24
S
+ B
−
HA17431
Transformer specification
example
EI-22 type core
(H7C18 × 06Z)
Gap length
lg = 0.3mm
Transformer coil example
P: 0.5¿80T/570µH
S: 0.5¿16T Bifiler/22µH
B: 0.2¿44T/170µH
+
+ 1.8k
− 1000µ
10V
330
3.3µ
+
−
3.3k DC
5V, 3A
OUTPUT
B
4.7k
HA17431
HA17384H,
HA17385H
−
0.1µ
Vref
COMP
150k
100p
RT
10k
FB
VIN
CS
OUT
RT/CT
GND
CT
3300p
470p
When the error
amplifier is not used
Vref
COMP
Photocoupler
(for output control)
1
2W
1k
1k
4.7k
2SK1567
51
OVP input
FB
0.8mA VIN
Bleeder resistor
(adjuster according
to the rating of the
Photocoupler)
CS
OUT
RT/CT
GND
(Operation Theory)
On the secondary side (S) of the flyback converter,
error amplification is carried out by a shunt
regulator and photocoupler.
The voltage of the backup coil (B) is not monitored,
which differs from the application example (1).
In addition, OVP operates on the secondary side
(S) using a photocoupler.
Refer to the application example (1) for the other
notes.
Figure 13 Secondary Voltage Sensing Flyback Converter
25
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Application Examples for Fuller Exploitation of Power Supply Functions
A number of application examples are briefly described below.
1. Soft start
A soft start is a start method in which the PWM pulse width is gradually increased when the power
supply is activated. This prevents the stress on the transformer and switch element caused by a rapid
increase in the PWM pulse width, and also prevents overshoot when the secondary-side output voltage
rises. The circuit diagram is shown in figure 14.
VIN 7
DIN
IO
800µA typ
Vref
5V
−
FB 2
+
EA
8
1
(4.4V)
VREF
(5V)
RCU
COMP
D1
D2
(3.7V)
2.5V
CST
(3V)
IC internal circuit
(around error amp.)
2R
(1V)
R
1V
To power supply
detection
comparator
External circuit
(only partially shown)
Figure 14 Circuit Diagram for Soft Start
Operation: In this circuit, error amp output source current IO (800 µA typ.) gradually raises the switch
element current detection level, using a voltage slope that charges soft start capacitance C ST. When the
voltage at each node is at the value shown in parentheses in the figure, the soft start ends. The soft start
time is thus given by the following formula:
TST = (3.7 V/800 µA) × CST ≈ 4.62 CST (ms)
(CST unit: µF)
External parts other than CST operate as follows:
• Diode D1
: Current detection level shift and current reverse-flow prevention.
• Diode D2
: Together with diode DIN in the IC, CST charge drawing when power supply falls.
• Resistance RCU : For CST charge-up at end of soft start. (Use a high resistance of the order of several
hundred kΩ.)
Note: During a soft start, since PWM pulses are not output for a while after the IC starts operating, there
is a lack of energy during this time, and intermittent mode may be entered. In this case, the
capacitance between Vref and GND should be increased to around 4.7 µF to 10 µF.
26
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
2. OVP latch output overvoltage protection (the HA17384H and HA17385H only)
The OVP latch is incorporated in the error amp input pin (FB). If the FB pin is pulled up to 7.0 V typ.
just once when the power supply enters any kind of error state, IC operation can be halted and held as it
is (latched). To reset the latch, drop the IC’s supply voltage to 7.0 V typ. or below momentarily.
An OVP latch application example is shown in figure 15.
VIN
R3
10k
2SA1029
FB
−
2
+
2.5V
7.0V
EA
Error amplifier
1
−
OVP
+
OVP comparator
1k
COMP
R1
R2
10k
47k
HA17431
(Vref ≈ 2.5V)
External circuit
(only partially shown)
Inside IC
Figure 15 Example of OVP Latch Application Circuit
This circuit protects the system by causing latch operation in the event of an overload or load short. In
the steady state, the error amp input/output pins operate at 2.5 V typ., but if the load becomes heavy the
FB pin level drops and the COMP pin level rises. As shown in the figure, this is detected by the
HA17431 shunt regulator, and the FB pin level is pulled up, operating the OVP latch.
The operation parameters are as follows:
COMP pin voltage detection level: Vth = (R1 + R2) / R2 × 2.5 V
27
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Notice for Use
1. OVP Latch Block
• Case
When DC power is applied directly as the power supply of the HA17384H, HA17385H, without using
the transformer backup coil. Also, when high-frequency noise is superimposed on the V IN pin.
• Problem
The IC may not be turn on in the case of a circuit in which V IN rises quickly (10 V/100 µs or faster),
such as that shown in figure 16. Also, the OVP latch may operate even though the FB pin is normally at
VOVP or below after the IC is activated.
• Reason
Because of the IC circuit configuration, the timer latch block operates first.
• Remedy (counter measure)
Take remedial action such as configuring a time constant circuit (RB, C B) as shown in figure 17, to keep
the VIN rise speed below 10 V/100 µs. Also, if there is marked high-frequency noise on the V IN pin, a
noise cancellation capacitor (C N) with the best possible high-frequency characteristics (such as a
ceramic capacitor) should be inserted between the V IN pin and GND, and close to the VIN pin.
When configuring an IC power supply with an activation resistance and backup winding, such as an
AC/DC converter, the rise of VIN will normally be around 1 V/100 µs, and there is no risk of this problem
occurring, but careful attention must be paid to high-frequency noise.
Also, this phenomenon is not occuring to the HA17384S, because OVP function is not built-in.
Input
Output
VIN
VIN
HA17384
Series
Feedback
GND
Figure 16 Example of Circuit with Fast VIN Rise Time
28
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Input
Output
Time constant
circuit
RB
51Ω
CN
VIN
VIN
18V
CB
1µF
Feedback
HA17384
Series
+
GND
Figure 17 Sample Remedial Circuit
2. Externally Synchronized Operation
• Case
When, with a power supply using the HA17384S/H or HA17385H, externally synchronized operation is
performed by applying an external syncronous signal to the RT /CT pin (pin 4).
• Problem
Synchronized operation may not be possible if the amplitude of the external syncronous signal is too
large.
• Reason
The RT /CT pin falls to a potential lower than the ground.
• Remedy (counter measure)
In this case, clamping is necessary using a diode with as small a VF value as possible, such as a schottky
barrier diode, as shown in figure 18.
Vref
HA17384
Series
RT
External
synchronous
signal
CT
47 0.01µF
Figure 18 Sample Remedial Circuit
29
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Package Dimensions
Unit: mm
6.3
7.4 Max
9.6
10.6 Max
8
5
1
0.89
4
1.3
7.62
0.1 Min
2.54 Min 5.06 Max
1.27 Max
+ 0.10
0.25 – 0.05
0.48 ± 0.10
2.54 ± 0.25
0° – 15°
Hitachi Code
JEDEC
EIAJ
Mass (reference value)
DP-8
Conforms
Conforms
0.54 g
Unit: mm
3.95
4.90
5.3 Max
5
8
*0.22 ± 0.03
0.20 ± 0.03
4
1.75 Max
1
0.75 Max
+ 0.10
6.10 – 0.30
1.08
*0.42 ± 0.08
0.40 ± 0.06
+ 0.11
0.14 – 0.04
0° – 8°
1.27
+ 0.67
0.60 – 0.20
0.15
0.25 M
*Dimension including the plating thickness
Base material dimension
30
Hitachi Code
JEDEC
EIAJ
Mass (reference value)
FP-8DC
Conforms
—
0.085 g
HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
Cautions
1. Hitachi neither warrants nor grants licenses of any rights of Hitachi’s or any third party’s patent,
copyright, trademark, or other intellectual property rights for information contained in this document.
Hitachi bears no responsibility for problems that may arise with third party’s rights, including
intellectual property rights, in connection with use of the information contained in this document.
2. Products and product specifications may be subject to change without notice. Confirm that you have
received the latest product standards or specifications before final design, purchase or use.
3. Hitachi makes every attempt to ensure that its products are of high quality and reliability. However,
contact Hitachi’s sales office before using the product in an application that demands especially high
quality and reliability or where its failure or malfunction may directly threaten human life or cause risk
of bodily injury, such as aerospace, aeronautics, nuclear power, combustion control, transportation,
traffic, safety equipment or medical equipment for life support.
4. Design your application so that the product is used within the ranges guaranteed by Hitachi particularly
for maximum rating, operating supply voltage range, heat radiation characteristics, installation
conditions and other characteristics. Hitachi bears no responsibility for failure or damage when used
beyond the guaranteed ranges. Even within the guaranteed ranges, consider normally foreseeable
failure rates or failure modes in semiconductor devices and employ systemic measures such as failsafes, so that the equipment incorporating Hitachi product does not cause bodily injury, fire or other
consequential damage due to operation of the Hitachi product.
5. This product is not designed to be radiation resistant.
6. No one is permitted to reproduce or duplicate, in any form, the whole or part of this document without
written approval from Hitachi.
7. Contact Hitachi’s sales office for any questions regarding this document or Hitachi semiconductor
products.
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Copyright ' Hitachi, Ltd., 1998. All rights reserved. Printed in Japan.
31