AN8021NS PANASONIC

Document overview

  • Manufacturer or author: Provided By digicamel.com
  • PDF pages: 4

Technical content

External excitation flyback AC-DC switching power supply control IC n Overview The AN8021S is a switching power supply control IC that controls the power supply from the primary side. It is optimal for relatively small switching power supplies. All rarely used functions have been removed from the AN8021S and as a result it is an extremely easy-to-use compact device. Furthermore, internal settings are implemented as many as we can, cost cut is possible with reduced external parts. n Features

  • Supports operation at switching frequencies up to 700 kHz and achieves a 35 ns output rise time and a 25 ns output fall time.
  • Extremely low pre-startup current consumption of 70 mA (typical) allows a significantly smaller startup resistor to be used.
  • Totem pole circuit structure adopted in the output block.
  • Output current absolute maximum rating of –1.0 A (peak) for direct driving of power MOSFET.
  • Pulse-by-pulse overcurrent protection circuit
  • Low voltage malfunction prevention circuit On/off: 14.2 V/9.2 V
  • Timer latch and overvoltage protection functions
  • Package: SONF-8D n Applications
  • Switching power supplies SOP008-P-0225C Unit: mm n Block Diagram OVP Start/Stop OSC5 RT CT TIM/OVP OCL FB V REF PWM4.2 V Drive Reset CLM V OUT GND CLM IFB

2 V CC

5.01±0.20 (1.05) 0.40(0.60) 0.50±0.20 0° to 10° 4.30±0.20 1.75max. 1.45±0.100.10±0.10 6.40±0.20 0.15 +0.10–0.05 Seating plane 1.27 +0.10 –0.05 0.10

AN8021NS Voltage Regulators n Absolute Maximum Ratings Parameter Symbol Rating Unit Supply voltage V CC 35 V OVP pin allowable application voltage VOVP V CC V CLM pin allowable application voltage VCLM - 0.3 to +7.0 V Supply current I CC ¾ mA Steady-state output current I O +150 mA Peak output current I OP –1 000 mA IFB pin allowable application current IFB -5m A Power dissipation *2 PD 122 mW Operating temperature *1 Topr -30 to +85 °C Storage temperature *1 Tstg -55 to +150 °C Notes) 1. *1: Items other than the storage temperature and operating temperature are all stipulated for an ambient temperature Ta = 25°C. *2: Applies when Ta = 85°C for the independent IC without a heat sink. 2. Currents or voltages may not be applied to any pins not stipulated above. For circuit currents, a positive (+) value indicates current flowing into the IC, and a negative (-) value indicates current flowing out of the IC. n Pin Descriptions Pin No. Symbol Description 1V OUT Direct power MOSFET drive output 2V CC Power supply. This pin monitored, and has threshold voltages for startup, stop, OVP reset, and other functions. 3 TIM/OVP OVP (overvoltage protection) and timer latch functions. OVP: Accepts a power supply overvoltage detection signal. When a high-level signal is input, internal circuits are turned off and this state is latched. To reset this OVP latched state, the VCC voltage should be lowered to below the release voltage. Timer latch: The IC detects output voltage drops due to overcurrent states in the power supply output by monitoring the magnitude of the current input to the IFB pin. In particular, when the current I IFB has fallen below a certain level, a charge current flows into the capacitor connected to this pin externally. When that capacitor is charged to the OVP threshold voltage, OVP operates and the IC keeps a stopped state.

4 IFB Input for the current feedback signal provided from a photocoupler of the power supply

output.

5 RT Connection for the resistor that determines the charge and discharge currents of the triangular

wave. In this device, the charge and discharge currents are the same. 6 CT Connection for the capacitor used to generate the triangular wave. 7 CLM Pulse-by-pulse overcurrent protection input. Normally, an external filter is required.

8 GND Ground

Voltage Regulators AN8021NS n Recommended Operating Range Parameter Symbol Range Unit Supply voltage V CC The stop voltage to 34 V Parameter Symbol Conditions Min Typ Max Unit Start voltage STRT V CC 13.0 14.2 15.4 V Stop voltage STOP V CC 8.5 9.2 9.9 V Standby mode bias current STB I CC V CC = 12 V 50 70 105 mA Operating bias current OPR I CC V CC = 34 V 5.9 7.8 9.6 mA OVP operating bias current 1 OVP1 I CC V CC = 20 V 2.4 3.0 3.6 mA OVP operating bias current 2 OVP2 I CC V CC = 10 V 0.44 0.55 0.66 mA OVP operating threshold voltage CVP V TH V CC = 18 V 5.4 6.0 6.6 V OVP release supply voltage OVPC V CC 7.6 8.4 9.2 V Timer latch charge current TIM I CH V CC = 18 V, RT = 19 kW- 15 -25 -35 mA Timer latch start feedback current TIM I FB V CC = 18 V - 0.37 - 0.5 - 0.63 mA Overcurrent protection threshold voltage CLM VTH V CC = 18 V -180 -200 -220 mV Pre-startup low-level output voltage STB VOL V CC = 12 V, IO = 10 mA ¾ 0.8 1.8 V Low-level output voltage V OL V CC = 18 V, IO = 100 mA ¾ 1.3 1.8 V High-level output voltage V OH V CC = 18 V, IO = -100 mA 15.0 16.5 ¾ V Oscillator frequency * fOSC1 V CC = 18 V 170 180 190 kHz Maximum duty factor D max V CC = 1 8 V 6 26 67 0 % Feedback current at 0% duty Dmin. I FB V CC = 18 V -1.1 -1.5 -1.9 mA Feedback current at maximum duty Dmax. I FB V CC = 18 V - 0.37 - 0.5 - 0.63 mA

  • Design reference data Note) The characteristics listed below are theoretical values based on the IC design and are not guaranteed. Parameter Symbol Conditions Min Typ Max Unit Oscillator frequency 2 f OSC2 Ta = -30°C to +85°C, VCC = 18 V 160 ¾ 240 kHz Overcurrent protection delay time CLM tDLY V CC = 18 V, no load. ¾ 200 ¾ ns Output voltage rise time t r V CC = 18 V, no load. ¾ 50 ¾ ns Output voltage fall time t f V CC = 18 V, no load. ¾ 25 ¾ ns n Electrical Characteristics at Ta = 25°C Note ) *: Provisional rating

AN8021NS Voltage Regulators Note) 1. The external circuits and circuit constants are provided as an example of a possible design. No guarantees are made with respect to these items for use in mass produced end products. 2. *: Former part number n Application Circuit Example V OUT CNCIS101(ON3131 *) etc. GND CLM PC 2 200 pF 0.47 W 100 mF 220 W 130 W 33 W 68 kW IFB V CC OVP Start/Stop OSC5 OCL FB V REF 4.2 V Reset CLM PWM Drive TIM/ OVP AC 0.22 mF 220 pF 1 kW 19 kW CT RT 15 V Zener diode n Usage Notes 1. Direct connection with the power supply pin (shorting to VCC ) In this device, pins other than pin 3 cannot be connected directly to the power supply pin (pin 2). Connection of any other pins to VCC will result in permanent damage to the device. 2. Direct connection with the ground pin (shorting to ground) In this device, pin 1 cannot be connected directly to the ground pin (pin 8). Connection of this pin to ground will result in permanent damage to the device.