Datasheet Rev 2, 5/2005 ACT30 ACT30 HIGH PERFORMANCE OFF-LINE CONTROLLER ActiveSwitcherTM IC Family FEATURES GENERAL DESCRIPTION The ACT30 is a high performance green-energy offline power supply controller. It features a scalable driver for driving external NPN or MOSFET transistors for line voltage switching. This proprietary architecture enables many advanced features to be integrated into a small package (TO-92 or SOT23-5), resulting in lowest total cost solution. Lowest Total Cost Solution 0.15W Standby Power Emitter Drive Allows Safe NPN Flyback Use Hiccup Mode Short Circuit Current Mode Operation Over-Current Protection Under-voltage Protection with Auto-restart Proprietary Scalable Output Driver Flexible Packaging Options (including TO-92) 65kHz or 100kHz Switching Frequency Selectable 0.4A to 1.2A Current Limit The ACT30 design has 6 internal terminals and is a pulse frequency and width modulation IC with many flexible packaging options. One combination of internal terminals is packaged in the space-saving TO-92 package (A/B/C/D versions) for 65kHz or 100kHz switching frequency and with 400mA or 800mA current limit. The E version (SOT23-5) can be configured for higher current limit. APPLICATIONS Battery Chargers Power Adaptors Standby Power Supplies Appliances Universal Off-line Power Supplies Consuming only 0.15W in standby, the IC features over-current, hiccup mode short circuit, and under-voltage protection mechanisms. The ACT30 is ideal for use in high performance universal adaptors and chargers. For highest performance versus cost and smallest PCB area, use the ACT30 in combination with the ACT32 CV/CC Controller. Figure 1. Simplified Application Circuit Active-Semi, Inc. -1- Confidential to Micro Bridge ACT30 ORDERING INFORMATION PART NUMBER SWITCHING FREQUENCY CURRENT LIMIT TEMPERATURE RANGE PACKAGE PINS ACT30AHT-A 65kHz 400mA -40°C to 85°C TO-92 3 ACT30BHT-A 65kHz 800mA -40°C to 85°C TO-92 3 ACT30CHT-A 100kHz 400mA -40°C to 85°C TO-92 3 ACT30DHT-A 100kHz 800mA -40°C to 85°C TO-92 3 ACT30EUC-T SELECTABLE ADJUSTABLE -40°C to 85°C SOT23-5 5 PIN CONFIGURATION ACT30A ACT30B ACT30C ACT30D 1 2 VDD 1 GND 2 FREQ 3 5 DRV1 4 DRV2 ACT30E 3 TO-92 SOT23-5 PIN NAME PIN DESCRIPTION PIN DESCRIPTION PIN NUMBER TO-92 SOT23-5 1 1 VDD Power Supply Pin. Connect to optocoupler's emitter. Internally limited to 5.5V max. Bypass to GND with a proper compensation network. 2 2 GND Ground DRV Driver Output (TO-92 Only). Connect to emitter of the high voltage NPN or MOSFET. For ACT30A/C, DRV pin is internally connected to DRV1. For ACT30B/D, DRV pin is internally connected to both DRV1 and DRV2. 5 DRV1 Driver Output 1 (SOT23-5 Only). Also used as supply input during startup. 4 DRV2 Driver Output 2 (SOT23-5 Only) 3 FREQ Frequency Select (SOT23-5 Only). This terminal has an internal 200kΩ pull down resistor. Connect to VDD for 100kHz operation. Connect to GND or leave unconnected for 65khz operation. 3 Active-Semi, Inc. -2- Confidential to Micro Bridge ACT30 ABSOLUTE MAXIMUM RATINGS (Note: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may affect device reliability.) PARAMETER VALUE UNIT -0.3 to 6 V 20 mA -0.3 to 18 V Internally limited A VDD, FREQ Pin Voltage VDD Current DRV, DRV1, DRV2 Voltage Continuous DRV, DRV1, DRV2 Current Maximum Power Dissipation TO-92 0.6 SOT23-5 0.39 W Operating Junction Temperature -40 to 150 °C Storage Temperature -55 to 150 °C 300 °C Lead Temperature (Soldering, 10 sec) ELECTRICAL CHARACTERISTICS (VDD = 4V, TJ = 25°C unless otherwise specified) PARAMETER SYMBOL TEST CONDITIONS VDD Start Voltage VSTART Rising edge DRV1 Start Voltage VDRVST DRV1 must be higher than this voltage to start up. DRV1 Short-Circuit Detect Threshold VSCDRV VDD Under-voltage Threshold VUV VDD Clamp Voltage Startup Supply Current IDDST MIN TYP MAX UNIT 4.75 5 5.25 V ACT30A/C 8.6 10.5 ACT30B/D 9.6 11.5 6.8 V V Falling edge 3.17 3.35 3.53 V 10mA 5.15 5.45 5.75 V 0.23 0.45 mA 0.7 1 mA VDD = 4V before VUV Supply Current IDD Switching Frequency fSW Maximum Duty Cycle DMAX Minimum Duty Cycle DMIN VDD = 4.6V 3.5 ILIM ACT30A/C VDD = VUV + ACT30B/D; ACT30E 0.1V with DRV1 = DRV2 400 Effective Current Limit ACT30A/B or FREQ = 0 55 65 85 ACT30C/D or FREQ = VDD 75 100 125 ACT30A/C, VDD = 4V 67 75 83 ACT30B/D, VDD = 4V 60 kHz % % mA 800 VDD to DRV1 Current Coefficient GGAIN -0.29 A/V VDD Dynamic Impedance RVDD 9 kΩ IDRV1 = IDRV2 = 0.05A 3.6 Ω DRV1 Rise Time 1nF load, 15Ω pull-up 30 ns DRV1 Fall Time 1nF load, 15Ω pull-up 20 ns DRV1 and DRV2 Switch Off Current Driver off, VDRV1 = VDRV2 = 10V 12 DRV1 or DRV2 Driver On-Resistance Active-Semi, Inc. RDRV1, 2 -3- 30 µA Confidential to Micro Bridge ACT30 STARTUP SEQUENCE FUNCTIONAL DESCRIPTION Figure 1 shows a Simplified Application Circuit for the ACT30. Initially, the small current through resistor R1 charges up the capacitor C1, and the BJT acts as a follower to bring up the DRV1 voltage. An internal regulator generates a VDD voltage equal to VDRV1 – 3.6V for ACT30A/C (VDRV1 – 4.6V for ACT30B/D) but limits it to 5.5V max. As VDD crosses 5V, the regulator sourcing function stops and VDD begins to drop due to its current consumption. As VDD voltage decreases below 4.75V, the IC starts to operate with increasing driver current. When the output voltage reaches regulation point, the optocoupler feedback circuit stops VDD from decreasing further. The switching action also allows the auxiliary windings to take over in supplying the C1 capacitor. Figure 3 shows a typical startup sequence for the ACT30. Figure 2 shows the Functional Block Diagram of the ACT30. The main components include switching control logic, two on-chip medium-voltage power-MOSFETs with parallel current sensor, driver, oscillator and ramp generator, current limit VC generator, error comparator, hiccup control, bias and undervoltage-lockout, and regulator circuitry. As seen in Figure 2, the design has 6 internal terminals. VDD is the power supply terminal. DRV1 and DRV2 are linear driver outputs that can drive the emitter of an external high voltage NPN transistor or N-channel MOSFET. This emitter-drive method takes advantage of the high VCBO of the transitor, allowing a low cost transistor such as ‘13003 (VCBO = 700V) or ‘13002 (VCBO = 600V) to be used for a wide AC input range. The slew-rate limited driver coupled with the turn-off characteristics of an external NPN result in lower EMI. To limit the auxiliary voltage, use a 12V zener diode for ACT30A/C or a 13V zener for ACT30B/D (D1 diode in Figure 1). The driver peak current is designed to have a negative voltage coefficient with respect to supply voltage VDD, so that lower supply voltage automatically results in higher DRV1 peak current. This way, the optocoupler can control VDD directly to affect driver current. Even though up to 2MΩ startup resistor (R1) can be used due to the very low startup current, the actual R1 value should be chosen as a compromise between standby power and startup time delay. DRV1 9k ‡ − + REGULATOR VDD DRV2 3.6V (ACT30A/C) 4.6V (ACT30B/D) BIAS & UVLO HICCUP CONTROL FREQ OSC & RAMP CURRENT † PFWM SWITCHING CONTROL LOGIC SLEW 1x 200k 56x 56x 20k ERROR COMP ILIM VC GENERATOR 4.75V − + + − 40 20k 10uA/V GND † ‡ GND FREQ terminal wire-bonded to VDD in ACT30C/D (TO-92) DRV2 terminal wire-bonded to DRV1 in ACT30B/D (TO-92) Figure 2. Functional Block Diagram Active-Semi, Inc. -4- Confidential to Micro Bridge ACT30 VAC pulse-skipped VDRVST VDRV1 5V VDD IPRIMARY VOUT Figure 3. Startup Waveforms NORMAL OPERATION CURRENT LIMIT ADJUSTMENT In normal operation, the feedback signal from the secondary side is transmitted through the optocoupler as a current signal into VDD pin, which has dynamic impedance of 9kΩ. The resulting VDD voltage affects the switching of the IC. As seen from the Functional Block Diagram, the Current Limit VC Generator uses the VDD voltage difference with 4.75V to generate a proportional offset at the negative input of the Error Comparator. The IC's proprietary driver arrangement allows the current limit to be easily adjusted between 400mA and 1.2A. To understand this, the drivers have to be utilized as linear resistive devices with typically 3.6Ω (rather than as digital output switches). The current limit can then be calculated through linear combination as shown in Figure 4. For TO-92 package, the ACT30A/C are preprogrammed to 400mA current limit and The drivers turn on at the beginning of each switching cycle. The current sense resistor current, which is a fraction of the transformer primary current, increases with time as the primary current increases. When the voltage accross this current sense resistor plus the oscillator ramp signal equals Error Comparator's negative input voltage, the drivers turn off. Thus, the peak DRV1 current has a negative voltage coefficent of -0.29A/V and can be calculated from the following: DRV1 IDRV1PEAK = 0.29A/V • (4.75V – VDD) DRV2 ILIM = 400 mA DRV2 DRV1 DRV2 RD 7 . 2 Ω + RD ILIM = 400 mA • 3.6Ω + RD DRV1 ILIM = 800 mA for VDD < 4.75V and duty cycle < 50%. When the output voltage is lower than regulation, the current into VDD pin is zero and VDD voltage decreases. At VDD = VUV = 3.35V, the peak DRV1 current has maximum value of 400mA. RD DRV1 DRV2 R ILIM = 400mA • 2 + D 3 .6Ω Figure 4. Driver Output Configurations Active-Semi, Inc. -5- Confidential to Micro Bridge ACT30 the ACT30B/D are preprogrammed to 800mA current limit. For ACT30E (SOT23-5) packages, both DRV1 and DRV2 terminals are provided. SHORT CIRCUIT HICCUP When the output is short circuited, the ACT30 enters hiccup mode operation. In this condition, the auxiliary supply voltage collapses. An on-chip detector compares DRV1 voltage during the off-time of each cycle to 6.8V. If DRV1 voltage is below 6.8V, the IC will not start the next cycle, causing both the auxiliary supply voltage and VDD to reduce further. The circuit enters startup mode when VDD drops below 3.35V. This hiccup behaviour continues until the short circuit is removed. In this behavior, the effective duty cycle is very low resulting in very low short circuit current. PULSE SKIPPING The PFWM Switching Control Logic block operates in different modes depending on the output load current level. At light load, the VDD voltage is around 4.75V. The energy delivered by each switching cycle (with minimum on time of 500ns) to the output causes VDD to increase slightly above 4.75V. The FPWM Switching Control Logic block is able to detect this condition and prevents the IC from switching until VDD is below 4.75V again. This results in a pulse-skipping action with fixed pulse width and varying frequency, and low power consumption because the switching frequency is reduced. Typical system standby power consumption is 0.15W. To make sure that the IC enters hiccup mode easily, the transformer should be constructed so that there is close coupling between secondary and auxiliary, so that the auxiliary voltage is low when the output is short-circuited. This can be achieved with the primary/auxiliary/secondary sequencing from the bobbin. APPLICATION INFORMATION IC EXTERNAL POWER TRANSISTOR The ACT30 allows a low-cost high voltage power NPN transistor such as ‘13003 or ‘13002 to be used safely in flyback configuration. The required collector voltage rating for VAC = 265V with full output load is at least 600V to 700V. As seen from Figure 5, NPN Reverse Bias Safe Operation Area, the breakdown voltage of an NPN is significantly improved when it is driven at its emitter. Thus, the ACT30+’13002 or ‘13003 combination meet the necessary breakdown safety requirement even though RCC circuits using ‘13002 or ‘13003 do not. Table 1 lists the breakdown voltage of some transistors appropriate for use with the ACT30. Base-Drive Safe Region (RCC) VCEO VCBO VCEO IC MJE13002 600V 300V 1.5A 8 TO-126 MJE13003, KSE13003 700V 400V 1.5A 8 TO-126 STX13003 700V 400V 1A 8 TO-92 Active-Semi, Inc. VCBO VC Figure 5. NPN Reverse Bias Safe Operation Area The power dissipated in the NPN transistor is equal to the collector current times the collector-emitter voltage. As a result, the transistor must always be in saturation when turned on to prevent excessive power dissipation. Select an NPN transistor with sufficiently high current gain (hFEMIN > 8) and a base drive resistor (R2 in Figure 1) low enough to ensure that the transistor easily saturates. Table 1. Recommended Power Transistors List DEVICE EmitterDrive Safe Region (ACT30) hFEMIN PACKAGE -6- Confidential to Micro Bridge ACT30 Figure 6. A 3.75W Charger Using ACT30A in combination with ACT32 APPLICATION EXAMPLE LAYOUT CONSIDERATIONS The application circuit in Figure 6 provides a 5V/0.75A constant voltage/constant current output. An ACT30A is used in combination with the ACT32 for highest efficiency and lowest component count. The following should be observed when doing layout for the ACT30: 1. Use a "star point" connection at the GND pin of ACT30 for the VDD bypass components (C5 and C6 in Figure 6), the input filter capacitor (C2 in Figure 6) and other ground connections on the primary side. To change the constant output voltage VOUTCV and constant current limit IOUTCC, modify R7 and R6 as following: R6 = 250mV/IOUTCC 2. Keep the loop across the input filter capacitor, the transformer primary windings, and the high voltage transistor, and the ACT30 as small as possible. The performance of this circuit is summarized in Table 2. 3. Keep ACT30 pins and the high voltage transistor pins as short as possible. R7 = 80kΩ • [(VOUTCV - 1V)/3.8V - 1] Table 2. System Performance of Circuit in Figure 6 110VAC 220VAC Standby Power 0.09W 0.15W Current Limit 0.75A 0.75A Full Load Efficiency 65% 67% Active-Semi, Inc. 4. Keep the loop across the secondary windings, the output diode, and the output capacitors as small as possible. 5. Allow enough copper area under the high voltage transistor, output diode, and current shunt resistor for heat sink. -7- Confidential to Micro Bridge ACT30 PACKAGE OUTLINE TO-92 PACKAGE OUTLINE AND DIMENSIONS (AMMO TAPE PACKING) DIMENSION IN MILIMETERS DIMENSION IN INCHES MIN MAX MIN MAX A 3.300 3.700 0.130 0.146 A1 1.100 1.400 0.043 b 0.380 0.550 c 0.360 D 4.400 D1 3.430 E 4.300 SYMBOL e e1 DIMENSION IN INCHES MIN MAX MIN MAX ∆k -1.0 1.0 -0.039 0.039 0.055 F1, F2 2.2 2.8 0.087 0.110 0.015 0.022 H 19 21 0.748 0.827 0.510 0.014 0.020 H0 15.5 16.5 0.610 0.650 4.700 0.173 0.185 L1 2.5 P 12.4 13.0 0.488 0.512 ∆P -1.0 1.0 -0.039 0.039 P0 12.5 12.9 0.492 0.508 0.104 P1 3.55 4.15 0.140 0.163 0.063 P2 6.05 6.65 0.238 0.262 0.015 Q1 3.8 4.2 0.150 0.165 t1 0.35 0.45 0.014 0.018 t2 0.15 0.25 0.006 0.010 W 17.5 19 0.689 0.748 W0 5.5 6.5 0.217 0.256 W1 8.5 9.5 0.335 0.374 0.135 4.700 1.270 TYP 2.440 Φ h DIMENSION IN MILIMETERS 2.640 0.169 0.380 0.185 0.050 TYP 0.096 1.600 0.000 SYMBOL 0.000 W2 Active-Semi, Inc. -8- 0.098 1.0 0.039 Confidential to Micro Bridge ACT30 SOT23-5 PACKAGE OUTLINE AND DIMENSIONS SYMBOL DIMENSION IN MILIMETERS DIMENSION IN INCHES MIN MAX MIN MAX A 1.050 1.250 0.041 0.049 A1 0.000 0.100 0.000 0.004 A2 1.050 1.150 0.041 0.045 b 0.300 0.400 0.012 0.016 c 0.100 0.200 0.004 0.008 D 2.820 3.020 0.111 0.119 E 1.500 1.700 0.059 0.067 E1 2.650 2.950 0.104 0.116 e e1 L 0.950 TYP 1.800 2.000 0.700 REF 0.037 TYP 0.071 0.079 0.028 REF L1 0.300 0.600 0.012 0.024 θ 0° 8° 0° 8° Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. Users should evaluate each product to make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use as critical components in life-support devices or systems. Active-Semi, Inc. does not assume any liability arising out of the use of any product or circuit described in this datasheet, nor does it convey any patent license. 44081 Old Warm Springs Blvd, Fremont, California 94538, USA Active-Semi, Inc. -9- Confidential to Micro Bridge