Manufacturer Part NumberHA17384
DescriptionHigh Speed Current Mode PWM Control IC for Switching Power Supply
ManufacturerHitachi Semiconductor
HA17384 datasheet

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High Speed Current Mode PWM Control IC
for Switching Power Supply
ADE-204-028A (Z)
2nd Edition
Nov. 1999
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, high-
speed, 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.

HA17384 Summary of contents

  • Page 1

    ... 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 “ ...

  • Page 2

    ... 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) * TSD function (thermal shut-down protection) * Protect function by zener diode (between power input and GND) Note: 1 ...

  • Page 3

    ... PWM Pulse output pin 7 V Power supply voltage input pin IN 8 Vref Reference voltage 5V output pin Note: 1. Overvoltage protection (OVP) input is usable only for the HA17384H and HA17385H. Additional Function TSD OVP (Thermal shut- (Over voltage down protection) protection) — — ...

  • Page 4

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Block Diagram COMP (OVP input) 7. RT/CT 4 8.4 mA Note: 1. Blocks with bold line are not included in HA17384SPS/SRP. 4 0.8mA UVL1 6.5V 1 OVP 2 Vref latch (2.5V OVP + TSD F sense 2R R 160 C CS latch PWM LOGIC ...

  • Page 5

    ... Power dissipation Operating temperature Junction temperature Storage temperature Notes: 1. For the HA17384HPS and HA17385HPS, This value applies temperatures above this, 8.3 mW/ C derating should be applied. For the HA17384SPS, This value applies temperatures above this, 8.3 mW/ C derating should be applied ...

  • Page 6

    ... Applies to the HA17384HPS/HRP and HA17385HPS/HRP. 4. Applies to the HA17384SPS/SRP Ambient Temperature range if the substrate wiring 63 C range if the substrate wiring 68 C range if the substrate wiring ...

  • Page 7

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Electrical Characteristics (The condition is 25°C, V Reference Part Item Symbol Reference output voltage Vref Line regulation Regline Load regulation Regload Output short current los Temperature stability Output noise voltage V Notes: 1. Reference value for design. Triangular Wave Oscillator Part ...

  • Page 8

    ... Output source current High level output voltage Low level output voltage OVP latch threshold voltage OVP (FB) terminal input current OVP latch reset V voltage IN Note: 1. These values are not prescribe to the HA17384SPS/SRP because OVP function is not included. 8 Symbol Min Typ Max V 2.42 2.50 2. — ...

  • Page 9

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Electrical Characteristics (cont) Current Sensing Part Item Symbol Voltage gain A Maximum sensing voltage Vth Power supply voltage PSRR rejection ratio Input bias current I Current sensing tpd response time Notes: 1. The gain this case is the ratio of error amplifier output change to the current-sensing threshold voltage change ...

  • Page 10

    ... Overheat protection Tj TSD starting temperature Notes: 1. These values are not prescribe to the HA17384SPS/SRP because OVP function is not included 8 case of the HA17384H These values are not prescribe to the HA17384SPS/SRP because TSD function is not included. 4. Reference value for design. ...

  • Page 11

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Timing Chart Signal Name Power ON Input voltage V Pin UVL1 Internal signal which 0V cannot be externally monitored. Reference voltage 0V Vref Pin 8 UVL2 Internal signal which 0V cannot be externally monitored. Oscillation voltage of 0V triangular wave R /C Pin operates and PWM output stops ...

  • Page 12

    ... 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 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 ...

  • Page 13

    ... At power OFF, the input voltage of the transformer gradually decreases and then V according to the input voltage. When 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 Power switch ...

  • Page 14

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP CS terminal Figure 3 Operation Diagram of Current Sensing Part Point 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 1.0 0.8 0.6 0.4 Light load 1.4V 0 Error Amplifier Output Voltage Vcomp (V) ...

  • Page 15

    ... 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). ...

  • Page 16

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP A. Control in the case of heavy load B. Control in the case of light load 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 ...

  • Page 17

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Main Characteristics Supply Current vs. Supply Voltage (HA17384S/ fosc = 52kHz Latch current 5 (HA17384H Power supply voltage V Standby Current/Latch Current vs. Supply Voltage Exploded diagram of the small current part from the above figure (HA17384S/H) 2 1.5 1.0 Latch current (HA17384H) 0 ...

  • Page 18

    ... Terminal Voltage 9.5 terminal voltage T 9.0 8.5 8 10V or more (HA17384S/ 7.6V or more (HA17385H Supply voltage V IN Reference Voltage vs. Ambient Temperature V = 15V Ambient temperature Discharge Current vs. Ambient Temperature T V =15 V ...

  • Page 19

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP 500 200 100 500 Figure 7 Oscillation Frequency vs. Timing Resistance Case 1. Setting large maximum duty cycle. Case 2. Setting small maximum duty cycle. Figure 8 Relationship Between Triangular Wave and Maximum ON Duty of PWM Pulse Ta = 25¡ 10k 20k ...

  • Page 20

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP 100 500 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. ...

  • Page 21

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Oscillation Frequency vs. Ambient Temperature 15V 1000pF Dumax = 95 Dumax = 40 Ambient Temperature Rise/Fall Time of Output Pulse vs. Load Capacitance 250 V = 15V 200 150 100 1000 2000 Output load capacitance C Current Sensing Level vs ...

  • Page 22

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP 100 V = 15V Figure 10 Open Loop Gain Characterisrics of Error Amplifier 22 Gain A VO Phase Phase margin 100 1k 10k Error Amplifier Input Signal Frequency f (Hz) Unit gain frequency f = 1MHz Typ 120 = 60 Typ O 180 100k ...

  • Page 23

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Calculation of operation parameters 1. Maximum ON duty Du max (Refer to the right figure.) Du max = Oscillation frequency fosc fosc = { From the above two equations, the following two equations are obtained. 3. Equalization to device R 190 0.56 (1/Du max e 4. Equation to device C ...

  • Page 24

    ... R T 47k 10k HA17431 C T 3300p Notes PRIMARY 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 51 1kV FRD P DFG1C8 Figure 12 Primary Voltage Sensing Flyback Converter 24 Rectifier bridge diode + ...

  • Page 25

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Application Circuit Example (2) When the error amplifier is used Commercial AC 100V Line filter 2SA1029 10k 10k 47k HA17431 150k 100p R T 10k C T 3300p 470p When the error amplifier is not used COMP OVP input Bleeder resistor (adjuster according to the rating of the ...

  • Page 26

    ... 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 ...

  • Page 27

    ... 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 (latched). To reset the latch, drop the IC’ ...

  • Page 28

    ... 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 Problem The IC may not be turn on in the case of a circuit in which V such as that shown in figure 16 ...

  • Page 29

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Input 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 R Problem Synchronized operation may not be possible if the amplitude of the external syncronous signal is too large. Reason The R /C pin falls to a potential lower than the ground ...

  • Page 30

    ... HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP Package Dimensions 10.6 Max 8 1 0.89 2.54 0.25 0.75 Max 1.27 *0.42 0.40 *Dimension including the plating thickness Base material dimension 30 9 1.3 1.27 Max 0.48 0.10 0 – 15 4.90 5.3 Max 0.08 0.06 0.15 0.25 M 7.62 + 0.10 0.25 – 0.05 Hitachi Code DP-8 JEDEC Conforms EIAJ Conforms Mass (reference value) 0. 0.10 6.10 – 0.30 1.08 0 – 0.67 0.60 – 0.20 Hitachi Code FP-8DC JEDEC Conforms EIAJ — ...

  • Page 31

    ... 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 ...