® TNY264/266-268 ® TinySwitch-II Family Enhanced, Energy Efficient, Low Power Off-line Switcher Product Highlights TinySwitch-II Features Reduce System Cost • Fully integrated auto-restart for short circuit and open loop fault protection–saves external component costs • Built-in circuitry practically eliminates audible noise with ordinary varnished transformer • Programmable line under-voltage detect feature prevents power on/off glitches–saves external components • Frequency jittering dramatically reduces EMI (~10 dB) –minimizes EMI filter component costs • 132 kHz operation reduces transformer size–allows use of EF12.6 or EE13 cores for low cost and small size • Very tight tolerances and negligible temperature variation on key parameters eases design and lowers cost • Lowest component count switcher solution Better Cost/Performance over RCC & Linears • Lower system cost than RCC, discrete PWM and other integrated/hybrid solutions • Cost effective replacement for bulky regulated linears • Simple ON/OFF control–no loop compensation needed • No bias winding–simpler, lower cost transformer ® EcoSmart –Extremely Energy Efficient • No load consumption < 50 mW with bias winding and < 250 mW without bias winding at 265 VAC input • Meets Blue Angel, Energy Star, and EC requirements • Ideal for cell-phone charger and PC standby applications High Performance at Low Cost • High voltage powered–ideal for charger applications • High bandwidth provides fast turn on with no overshoot • Current limit operation rejects line frequency ripple • Built-in current limit and thermal protection Description TinySwitch-II maintains the simplicity of the TinySwitch topology, while providing a number of new enhancements to further reduce system cost and component count, and to practically eliminate audible noise. Like TinySwitch, a 700 V power MOSFET, oscillator, high voltage switched current source, current limit and thermal shutdown circuitry are integrated onto a monolithic device. The start-up and operating power are derived directly from the voltage on the DRAIN pin, eliminating the need for a bias winding and associated circuitry. In addition, the + + Optional UV Resistor DC Output - Wide-Range HV DC Input D EN/UV BP TinySwitch-II S PI-2684-101700 Figure 1. Typical Standby Application. OUTPUT POWER TABLE 230 VAC ±15% PRODUCT(3) Adapter(1) 85-265 VAC Open Adapter(1) Open Frame(2) Frame(2) TNY264P or G 5.5 W 9W 4W 6W TNY266P or G TNY267P or G 10 W 13 W 15 W 19 W 6W 8W 9.5 W 12 W TNY268P or G 16 W 23 W 10 W 15 W Table 1. Notes: 1. Typical continuous power in a non-ventilated enclosed adapter measured at 50 ˚C ambient. 2. Maximum practical continuous power in an open frame design with adequate heat sinking, measured at 50 ˚C ambient (See key applications section for details). 3. Packages: P: DIP-8B, G: SMD-8B. Please see part ordering information. TinySwitch-II devices incorporate auto-restart, line undervoltage sense, and frequency jittering. An innovative design minimizes audio frequency components in the simple ON/OFF control scheme to practically eliminate audible noise with standard taped/varnished transformer construction. The fully integrated auto-restart circuit safely limits output power during fault conditions such as output short circuit or open loop, reducing component count and secondary feedback circuitry cost. An optional line sense resistor externally programs a line under-voltage threshold, which eliminates power down glitches caused by the slow discharge of input storage capacitors present in applications such as standby supplies. The operating frequency of 132 kHz is jittered to significantly reduce both the quasi-peak and average EMI, minimizing filtering cost. July 2001 TNY264/266-268 BYPASS (BP) DRAIN (D) REGULATOR 5.8 V LINE UNDER-VOLTAGE 240 µA 50 µA FAULT PRESENT AUTORESTART COUNTER 6.3 V BYPASS PIN UNDER-VOLTAGE + CURRENT LIMIT STATE MACHINE 5.8 V 4.8 V VI LIMIT RESET CURRENT LIMIT COMPARATOR - ENABLE + JITTER CLOCK 1.0 V + VT THERMAL SHUTDOWN DCMAX OSCILLATOR ENABLE/ UNDERVOLTAGE (EN/UV) 1.0 V S Q R Q LEADING EDGE BLANKING SOURCE (S) PI-2643-030701 Figure 2. Functional Block Diagram. Pin Functional Description DRAIN (D) Pin: Power MOSFET drain connection. Provides internal operating current for both start-up and steady-state operation. BYPASS (BP) Pin: Connection point for a 0.1 µF external bypass capacitor for the internally generated 5.8 V supply. ENABLE/UNDER-VOLTAGE (EN/UV) Pin: This pin has dual functions: enable input and line under-voltage sense. During normal operation, switching of the power MOSFET is controlled by this pin. MOSFET switching is terminated when a current greater than 240 µA is drawn from this pin. This pin also senses line under-voltage conditions through an external resistor connected to the DC line voltage. If there is no external resistor connected to this pin, TinySwitch-II detects its absence and disables the line undervoltage function. P Package (DIP-8B) G Package (SMD-8B) BP 1 8 S (HV RTN) S 2 7 S (HV RTN) S 3 EN/UV 4 5 D PI-2685-101600 Figure 3. Pin Configuration. SOURCE (S) Pin: Control circuit common, internally connected to output MOSFET source. SOURCE (HV RTN) Pin: Output MOSFET source connection for high voltage return. 2 B 7/01 TNY264/266-268 TinySwitch-II Functional Description TinySwitch-II combines a high voltage power MOSFET switch with a power supply controller in one device. Unlike conventional PWM (Pulse Width Modulator) controllers, TinySwitch-II uses a simple ON/OFF control to regulate the output voltage. The TinySwitch-II controller consists of an Oscillator, Enable Circuit (Sense and Logic), Current Limit State Machine, 5.8 V Regulator, Bypass pin Under-Voltage Circuit, Over Temperature Protection, Current Limit Circuit, Leading Edge Blanking and a 700 V power MOSFET. TinySwitch-II incorporates additional circuitry for Line Under-Voltage Sense, Auto-Restart and Frequency Jitter. Figure 2 shows the functional block diagram with the most important features. Oscillator The typical oscillator frequency is internally set to an average of 132 kHz. Two signals are generated from the oscillator: the Maximum Duty Cycle signal (DCMAX) and the Clock signal that indicates the beginning of each cycle. The TinySwitch-II oscillator incorporates circuitry that introduces a small amount of frequency jitter, typically 8 kHz peak-to-peak, to minimize EMI emission. The modulation rate of the frequency jitter is set to 1 kHz to optimize EMI reduction for both average and quasi-peak emissions. The frequency jitter should be measured with the oscilloscope triggered at the falling edge of the DRAIN waveform. The waveform in Figure4 illustrates the frequency jitter of the TinySwitch-II. 600 500 V DRAIN PI-2741-041901 Enable Input and Current Limit State Machine The enable input circuit at the EN/UV pin consists of a low impedance source follower output set at 1.0 V. The current through the source follower is limited to 240 µA. When the current out of this pin exceeds 240 µA, a low logic level 400 300 (disable) is generated at the output of the enable circuit. This enable circuit output is sampled at the beginning of each cycle on the rising edge of the clock signal. If high, the power MOSFET is turned on for that cycle (enabled). If low, the power MOSFET remains off (disabled). Since the sampling is done only at the beginning of each cycle, subsequent changes in the EN/UV pin voltage or current during the remainder of the cycle are ignored. The Current Limit State Machine reduces the current limit by discrete amounts at light loads when TinySwitch-II is likely to switch in the audible frequency range. The lower current limit raises the effective switching frequency above the audio range and reduces the transformer flux density including the associated audible noise. The state machine monitors the sequence of EN/UV pin voltage levels to determine the load condition and adjusts the current limit level accordingly in discrete amounts. Under most operating conditions (except when close to noload), the low impedance of the source follower keeps the voltage on the EN/UV pin from going much below 1.0 V in the disabled state. This improves the response time of the optocoupler that is usually connected to this pin. 5.8 V Regulator and 6.3 V Shunt Voltage Clamp The 5.8 V regulator charges the bypass capacitor connected to the BYPASS pin to 5.8 V by drawing a current from the voltage on the DRAIN pin, whenever the MOSFET is off. The BYPASS pin is the internal supply voltage node for the TinySwitch-II. When the MOSFET is on, the TinySwitch-II operates from the energy stored in the bypass capacitor. Extremely low power consumption of the internal circuitry allows TinySwitch-II to operate continuously from current it takes from the DRAIN pin. A bypass capacitor value of 0.1 µF is sufficient for both high frequency decoupling and energy storage. In addition, there is a 6.3 V shunt regulator clamping the BYPASS pin at 6.3 V when current is provided to the BYPASS pin through an external resistor. This facilitates powering of TinySwitch-II externally through a bias winding to decrease the no load consumption to about 50 mW. BYPASS Pin Under-Voltage The BYPASS pin under-voltage circuitry disables the power MOSFET when the BYPASS pin voltage drops below 4.8 V. Once the BYPASS pin voltage drops below 4.8 V, it must rise back to 5.8 V to enable (turn-on) the power MOSFET. 200 100 0 136 kHz 128 kHz 0 5 10 Time (µs) Figure 4. Frequency Jitter. B 7/01 3 TNY264/266-268 Over Temperature Protection The thermal shutdown circuitry senses the die temperature. The threshold is typically set at 135 °C with 70 °C hysteresis. When the die temperature rises above this threshold the power MOSFET is disabled and remains disabled until the die temperature falls by 70 °C, at which point it is re-enabled. A large hysteresis of 70 °C (typical) is provided to prevent overheating of the PC board due to a continuous fault condition. Current Limit The current limit circuit senses the current in the power MOSFET. When this current exceeds the internal threshold (ILIMIT), the power MOSFET is turned off for the remainder of that cycle. The current limit state machine reduces the current limit threshold by discrete amounts under medium and light loads. The leading edge blanking circuit inhibits the current limit comparator for a short time (tLEB) after the power MOSFET is turned on. This leading edge blanking time has been set so that current spikes caused by capacitance and secondary-side rectifier reverse recovery time will not cause premature termination of the switching pulse. the power MOSFET is disabled beyond its normal 850 ms time until the line under-voltage condition ends. Line Under-Voltage Sense Circuit The DC line voltage can be monitored by connecting an external resistor from the DC line to the EN/UV pin. During power-up or when the switching of the power MOSFET is disabled in auto-restart, the current into the EN/UV pin must exceed 50 µA to initiate switching of the power MOSFET. During power-up, this is implemented by holding the BYPASS pin to 4.8 V while the line under-voltage condition exists. The BYPASS pin then rises from 4.8 V to 5.8V when the line undervoltage condition goes away. When the switching of the power MOSFET is disabled in auto-restart mode and a line undervoltage condition exists, the auto-restart counter is stopped. This stretches the disable time beyond its normal 850ms until the line under-voltage condition ends. The line under-voltage circuit also detects when there is no external resistor connected to the EN/UV pin (less than ~ 2 µA into pin). In this case the line under-voltage function is disabled. TinySwitch-II Operation Auto-Restart In the event of a fault condition such as output overload, output short circuit, or an open loop condition, TinySwitch-II enters into auto-restart operation. An internal counter clocked by the oscillator gets reset every time the EN/UV pin is pulled low. If the EN/UV pin is not pulled low for 50 ms, the power MOSFET switching is normally disabled for 850 ms (except in the case of line under-voltage condition in which case it is disabled until the condition is removed). The auto-restart alternately enables and disables the switching of the power MOSFET until the fault condition is removed. Figure 5 illustrates auto-restart circuit operation in the presence of an output short circuit. PI-2699-030701 In the event of a line under-voltage condition, the switching of V 300 DRAIN 200 100 0 10 TinySwitch-II devices operate in the current limit mode. When enabled, the oscillator turns the power MOSFET on at the beginning of each cycle. The MOSFET is turned off when the current ramps up to the current limit or when the DCMAX limit is reached. As the highest current limit level and frequency of a TinySwitch-II design are constant, the power delivered to the load is proportional to the primary inductance of the transformer and peak primary current squared. Hence, designing the supply involves calculating the primary inductance of the transformer for the maximum output power required. If the TinySwitch-II is appropriately chosen for the power level, the current in the calculated inductance will ramp up to current limit before the DCMAX limit is reached. Enable Function TinySwitch-II senses the EN/UV pin to determine whether or not to proceed with the next switch cycle as described earlier. The sequence of cycles is used to determine the current limit. Once a cycle is started, it always completes the cycle (even when the EN/UV pin changes state half way through the cycle). This operation results in a power supply in which the output voltage ripple is determined by the output capacitor, amount of energy per switch cycle and the delay of the feedback. V DC-OUTPUT 5 The EN/UV pin signal is generated on the secondary by comparing the power supply output voltage with a reference voltage. The EN/UV pin signal is high when the power supply output voltage is less than the reference voltage. 0 1000 0 Time (ms) Figure 5. TinySwitch-II Auto-Restart Operation. 4 B 7/01 2000 In a typical implementation, the EN/UV pin is driven by an optocoupler. The collector of the optocoupler transistor isconnected to the EN/UV pin and the emitter is connected to TNY264/266-268 the SOURCE pin. The optocoupler LED is connected in series with a Zener diode across the DC output voltage to be regulated. When the output voltage exceeds the target regulation voltage level (optocoupler LED voltage drop plus Zener voltage), the optocoupler LED will start to conduct, pulling the EN/UV pin low. The Zener diode can be replaced by a TL431 reference circuit for improved accuracy. beginning of each clock cycle, it samples the EN/UV pin to decide whether or not to implement a switch cycle, and based on the sequence of samples over multiple cycles, it determines the appropriate current limit. At high loads, when the EN/UV pin is high (less than 240 µA out of the pin), a switching cycle with the full current limit occurs. At lighter loads, when EN/UV is high, a switching cycle with a reduced current limit occurs. ON/OFF Operation with Current Limit State Machine The internal clock of the TinySwitch-II runs all the time. At the At near maximum load, TinySwitch-II will conduct during nearly all of its clock cycles (Figure 6). At slightly lower load, it will “skip” additional cycles in order to maintain voltage regulation at the power supply output (Figure 7). At medium loads, cycles will be skipped and the current limit will be reduced (Figure8). At very light loads, the current limit will be reduced even further (Figure 9). Only a small percentage of cycles will occur to satisfy the power consumption of the power supply. V EN CLOCK D MAX The response time of the TinySwitch-II ON/OFF control scheme is very fast compared to normal PWM control. This provides tight regulation and excellent transient response. I DRAIN V DRAIN PI-2749-050301 Figure 6. TinySwitch-II Operation at Near Maximum Loading. Power Up/Down The TinySwitch-II requires only a 0.1 µF capacitor on the BYPASS pin. Because of its small size, the time to charge this capacitor is kept to an absolute minimum, typically 0.6 ms. Due to the fast nature of the ON/OFF feedback, there is no overshoot at the power supply output. When an external resistor (2 MΩ) is connected from the positive DC input to the EN/UV pin, the power MOSFET switching will be delayed during power-up until the DC line voltage exceeds the threshold (100 V). Figures 10 and 11 show the power-up timing waveform of TinySwitch-II V EN V EN CLOCK CLOCK D D MAX I DRAIN MAX I DRAIN V DRAIN V DRAIN PI-2667-090700 Figure 7. TinySwitch-II Operation at Moderately Heavy Loading. PI-2377-091100 Figure 8. TinySwitch-II Operation at Medium Loading. B 7/01 5 TNY264/266-268 V 100 V EN PI-2381-1030801 200 DC-INPUT 0 CLOCK 10 D V 5 MAX BYPASS 0 400 I DRAIN 200 V DRAIN 0 0 1 2 Time (ms) V DRAIN PI-2348-030801 Figure 11. TinySwitch-II Power-up without Optional External UV Resistor Connected to EN/UV Pin. PI-2661-072400 Figure 9. TinySwitch-II Operation at Very Light Load. 200 in applications with and without an external resistor (2 MΩ) connected to the EN/UV pin. 100 During power-down, when an external resistor is used, the power MOSFET will switch for 50 ms after the output loses regulation. The power MOSFET will then remain off without any glitches since the under-voltage function prohibits restart when the line voltage is low. V DC-INPUT 0 400 300 V 200 DRAIN 100 PI-2383-030801 200 V 100 DC-INPUT 0 0 Figure 12. Normal Power-down Timing (without UV). 200 100 10 0 V BYPASS 300 400 200 DC-INPUT V DRAIN 100 V DRAIN 0 0 1 0 Time (ms) Figure 10. TinySwitch-II Power-up with Optional External UV Resistor (2 MΩ) Connected to EN/UV Pin. 6 V 400 0 200 1 Time (s) 0 5 .5 PI-2395-030801 Figure 12 illustrates a typical power-down timing waveform of TinySwitch-II. Figure 13 illustrates a very slow power-down timing waveform of TinySwitch-II as in standby applications. The external resistor (2 MΩ) is connected to the EN/UV pin in this case to prevent unwanted restarts. B 7/01 2 0 2.5 Time (s) Figure 13. Slow Power-down Timing with Optional External (2 MΩ) UV Resistor Connected to EN/UV Pin. 5 TNY264/266-268 C8 680 pF Y1 Safety Shield T1 1 8 L2 3.3 µH D5 1N5819 C3 2.2 nF D1 1N4005 R2 200 kΩ D2 1N4005 85-265 VAC RF1 8.2 Ω 5 C1 3.3 µF 400 V C2 3.3 µF 400 V C6 100 µF 35 V +5V 500 mA RTN R8 270 Ω D6 1N4937 U2 LTV817 U1 D TNY264 TinySwitch-II Fusible D3 D4 1N4005 1N4005 4 C5 330 µF 16 V EN/UV R9 47 Ω BP Q1 2N3904 S R1 1.2 kΩ L1 2.2 mH R7 100 Ω C3 0.1 µF R3 22 Ω VR1 BZX79B3V9 3.9 V C7 10 µF 10 V R6 R4 1.2 Ω 1 Ω 1/2 W 1/2 W PI-2706-052301 Figure 14. 2.5 W Constant Voltage, Constant Current Battery Charger with Universal Input (85-265 VAC). The TinySwitch-II does not require a bias winding to provide power to the chip, because it draws the power directly from the DRAIN pin (see Functional Description above). This has two main benefits. First, for a nominal application, this eliminates the cost of a bias winding and associated components. Secondly, for battery charger applications, the current-voltage characteristic often allows the output voltage to fall close to zero volts while still delivering power. This type of application normally requires a forward-bias winding which has many more associated components. With TinySwitch-II, neither are necessary. For applications that require a very low no-load power consumption (50 mW), a resistor from a bias winding to the BYPASS pin can provide the power to the chip. The minimum recommended current supplied is 750 µA. The BYPASS pin in this case will be clamped at 6.3 V. This method will eliminate the power draw from the DRAIN pin, thereby reducing the no-load power consumption and improving fullload efficiency. Current Limit Operation Each switching cycle is terminated when the DRAIN current reaches the current limit of the TinySwitch-II. Current limit operation provides good line ripple rejection and relatively constant power delivery independent of input voltage. BYPASS Pin Capacitor The BYPASS pin uses a small 0.1 µF ceramic capacitor for decoupling the internal power supply of the TinySwitch-II. Application Examples The TinySwitch-II is ideal for low cost, high efficiency power supplies in a wide range of applications such as cellular phone chargers, PC standby, TV standby, AC adapters, motor control, appliance control and ISDN or a DSL network termination. The 132 kHz operation allows the use of a low cost EE13 or EF12.6 core transformer while still providing good efficiency. The frequency jitter in TinySwitch-II makes it possible to use a single inductor (or two small resistors for under 3 W applications if lower efficiency is acceptable) in conjunction with two input capacitors for input EMI filtering. The auto-restart function removes the need to oversize the output diode for short circuit conditions allowing the design to be optimized for low cost and maximum efficiency. In charger applications, it eliminates the need for a second optocoupler and Zener diode for open loop fault protection. Auto-restart also saves the cost of adding a fuse or increasing the power rating of the current sense resistors to survive reverse battery conditions. For applications requiring under-voltage lock out (UVLO), such as PC standby, the TinySwitch-II eliminates several components and saves cost. TinySwitch-II is well suited for applications that require constant voltage and constant current output. As TinySwitch-II is always powered from the input high voltage, it therefore does not rely on bias winding voltage. Consequently this greatly simplifies designing chargers that must work down to zero volts on the output. B 7/01 7 TNY264/266-268 2.5 W CV/CC Cell-Phone Charger As an example, Figure 14 shows a TNY264 based 5 V, 0.5 A, cellular phone charger operating over a universal input range (85-265 VAC). The inductor (L1) forms a π-filter in conjunction with C1 and C2. The resistor R1 damps resonances in the inductor L1. Frequency jittering operation of TinySwitch-II allows the use of a simple π-filter described above in combination with a single low value Y1-capacitor (C8) to meet worldwide conducted EMI standards. The addition of a shield winding in the transformer allows conducted EMI to be met even with the output capacitively earthed (which is the worst case condition for EMI). The diode D6, capacitor C3 and resistor R2 comprise the clamp circuit, limiting the leakage inductance turn-off voltage spike on the TinySwitch-II DRAIN pin to a safe value. The output voltage is determined by the sum of the optocoupler U2 LED forward drop (~1 V), and Zener diode VR1 voltage. Resistor R8 maintains a bias current through the Zener diode to ensure it is operated close to the Zener test current. A simple constant current circuit is implemented using the VBE of transistor Q1 to sense the voltage across the current sense resistor R4. When the drop across R4 exceeds the VBE of transistor Q1, it turns on and takes over control of the loop by driving the optocoupler LED. Resistor R6 assures sufficient voltage to keep the control loop in operation down to zero volts at the output. With the output shorted, the drop across R4 and R6 (~1.2 V) is sufficient to keep the Q1 and LED circuit active. Resistors R7 and R9 limit the forward current that could be drawn through VR1 by Q1 under output short circuit conditions, due to the voltage drop across R4 and R6. 10 and 15 W PC Standby Circuits Figures 15 and 16 show examples of circuits for PC standby applications. They both provide two outputs: an isolated 5 V and a 12V primary referenced output. The first, using TNY266P, provides 10W, and the second, using TNY267P, 15 W of output power. Both operate from an input range of 140 to 375VDC, corresponding to a 230 VAC or 100/115 VAC with doubler input. The designs take advantage of the line undervoltage detect, auto-restart and higher switching frequency of TinySwitch-II. Operation at 132 kHz allows the use of a smaller and lower cost transformer core, EE16 for 10 W and EE22 for 15 W. The removal of pin 6 from the 8 pin DIP TinySwitch-II packages provides a large creepage distance which improves reliability in high pollution environments such as fan cooled PC power supplies. 8 B 7/01 Capacitor C1 provides high frequency decoupling of the high voltage DC supply, only necessary if there is a long trace length from the DC bulk capacitors of the main supply. The line sense resistors R2 and R3 sense the DC input voltage for line undervoltage. When the AC is turned off, the under-voltage detect feature of the TinySwitch-II prevents auto-restart glitches at the output caused by the slow discharge of large storage capacitance in the main converter. This is achieved by preventing the TinySwitch-II from switching when the input voltage goes below a level needed to maintain output regulation, and keeping it off until the input voltage goes above the under-voltage threshold, when the AC is turned on again. With R2 and R3, giving a combined value of 4 MΩ, the power up under-voltage threshold is set at 200 VDC, slightly below the lowest required operating DC input voltage, for start-up at 170 VAC, with doubler. This feature saves several components needed to implement the glitch-free turn-off compared with discrete or TOPSwitch-II based designs. During turn-on the rectified DC input voltage needs to exceed 200 V under-voltage threshold for the power supply to start operation. But, once the power supply is on it will continue to operate down to 140 V rectified DC input voltage to provide the required hold up time for the standby output. The auxiliary primary side winding is rectified and filtered by D2 and C2 to create a 12 V primary bias output voltage for the main power supply primary controller. In addition, this voltage is used to power the TinySwitch-II via R4. Although not necessary for operation, supplying the TinySwitch-II externally reduces the device quiescent dissipation by disabling the internal drain derived current source normally used to keep the BYPASS pin capacitor (C3) charged. An R4 value of 10 kΩ provides 600 µA into the BYPASS pin, which is slightly in excess of the current consumption of TinySwitch-II. The excess current is safely clamped by an on-chip active Zener diode to 6.3 V. The secondary winding is rectified and filtered by D3 and C6. For a 15W design an additional output capacitor, C7, is required due to the larger secondary ripple currents compared to the 10W PC standby design. The auto-restart function limits output current during short circuit conditions, removing the need to over rate D3. Switching noise filtering is provided by L1 and C8. The 5V output is sensed by U2 and VR1. R5 is used to ensure that the Zener diode is biased at its test current. The Zener regulation method provides sufficient accuracy (typ. ± 3%). This is possible because TinySwitch-II limits the dynamic range of the optocoupler LED current, allowing the Zener diode to operate at near constant bias current. TNY264/266-268 PERFORMANCE SUMMARY Continuous Output Power: Efficiency: 140-375 VDC INPUT 10.24 W ≥ 75% C5 R1 2.2 nF 200 kΩ 1 kV C1 0.01 µF 1 kV U1 TNY266P D1 1N4005 R2 2 MΩ D2 1N4148 +12 VDC 20 mA C4 1 nF Y1 1 10 2 8 L1 10 µH 2A D3 1N5822 C6 1000 µF 10 V C8 470 µF 10 V +5 V (± 5%) 2A RTN 4 VR1 BZX79B3V9 5 T1 R3 2 MΩ D C2 82 µF 35 V EN BP R4 10 kΩ U2 SFH615-2 TinySwitch-II S R5 150 Ω C3 0.1 µF 50 V 0V PI-2713-040901 Figure 15. 10 W PC Standby Supply. PERFORMANCE SUMMARY Continuous Output Power: 15.24 W Efficiency: ≥ 78% 140-375 VDC INPUT C5 R1 2.2 nF 100 kΩ 1 kV C1 0.01 µF 1 kV U1 TNY267P D1 1N4005 +12 VDC 20 mA 1 10 2 8 L1 10 µH 3A D3 SB540 C6 1000 µF 10 V C7 1000 µF 10 V C8 470 µF 10 V +5 V (± 5%) 3A RTN 4 VR1 BZX79B3V9 5 T1 R3 2 MΩ D C2 82 µF 35 V R2 2 MΩ D2 1N4148 C4 1 nF Y1 EN BP S 0V R4 10 kΩ TinySwitch-II C3 0.1 µF 50 V U2 SFH615-2 R5 150 Ω PI-2712-040901 Figure 16. 15 W PC Standby Supply. B 7/01 9 TNY264/266-268 Key Application Considerations TinySwitch-II vs. TinySwitch Table 2 compares the features and performance differences between the TNY254 device of the TinySwitch family with the TinySwitch-II family of devices. Many of the new features TinySwitch TNY254 Function Switching Frequency and Tolerance Temperature Variation (0 - 100 °C)** 44 kHz ±10% (@25 °C) +8% eliminate the need for or reduce the cost of circuit components. Other features simplify the design and enhance performance. TinySwitch-II TNY264/266-268 TinySwitch-II Advantages 132 kHz ±6% (@25 °C) • Smaller transformer for low cost • Ease of design +2% • Manufacturability • Optimum design for lower cost Active Frequency Jitter N/A* ±4 kHz • Lower EMI minimizing filter component costs Transformer Audible Noise Reduction N/A* Yes - built into controller • Practically eliminates audible noise with ordinary dip varnished transformer – no special construction or gluing required Line UV Detect N/A* Single resistor programmable • Prevents power on/off glitches Current Limit Tolerance Temperature Variation (0 - 100 °C)** ± 11% (@25 °C) -8% ± 7% (@25 °C) 0% • Increases power capability and simplifies design for high volume manufacturing Auto-Restart N/A* 6% effective on-time • Limits output short-circuit current to less than full load current - No output diode size penalty. • Protects load in open loop fault conditions - No additional components required BYPASS Pin Zener Clamp N/A* Internally clamped to 6.3 V • Allows TinySwitch-II to be powered from a low voltage bias winding to improve efficiency and to reduce on-chip power dissipation DRAIN Creepage at Package 0.037” / 0.94 mm 0.137” / 3.48 mm • Greater immunity to arcing as a result of dust, debris or other contaminants build-up *Not available. ** See typical performance curves. Table 2. Comparison Between TinySwitch and TinySwitch-II. Design Output Power Table 1 (front page) shows the practical maximum continuous output power levels that can be obtained under the following conditions: 10 B 7/01 1. The minimum DC input voltage is 90 V or higher for 85 VAC input, or 240 V or higher for 230 VAC input or 115 VAC input with a voltage doubler. This corresponds to a filter capacitor of 3 µF/W for universal input and 1 µF/W for 230 or 115 VAC with doubler input. TNY264/266-268 2. A secondary output of 5 V with a Schottky rectifier diode. 3. Assumed efficiency of 77% (TNY267 & TNY268), 75% (TNY266) and 73% (TNY264). 4. The parts are board mounted with SOURCE pins soldered to sufficient area of copper to keep the die temperature at or below 100 °C. In addition to the thermal environment (sealed enclosure, ventilated, open frame, etc.), the maximum power capability of TinySwitch-II in a given application depends on transformer core size and design (continuous or discontinuous), efficiency, minimum specified input voltage, input storage capacitance, output voltage, output diode forward drop, etc., and can be different from the values shown in Table 1. Audible Noise The TinySwitch-II practically eliminates any transformer audio noise using simple ordinary varnished transformer construction. No gluing of the cores is needed. The audio noise reduction is accomplished by the TinySwitch-II controller reducing the current limit in discrete steps as the load is reduced. This minimizes the flux density in the transformer when switching at audio frequencies. Worst Case EMI & Efficiency Measurement Since identical TinySwitch-II supplies may operate at several different frequencies under the same load and line conditions, care must be taken to ensure that measurements are made under worst case conditions. When measuring efficiency or EMI verify that the TinySwitch-II is operating at maximum frequency and that measurements are made at both low and high line input voltages to ensure the worst case result is obtained. Layout Single Point Grounding Use a single point ground connection at the SOURCE pin for the BYPASS pin capacitor and the Input Filter Capacitor (see Figure 17). Primary Loop Area The area of the primary loop that connects the input filter capacitor, transformer primary and TinySwitch-II together should be kept as small as possible. Primary Clamp Circuit A clamp is used to limit peak voltage on the DRAIN pin at turnoff. This can be achieved by using an RCD clamp (as shown in Figure 14). A Zener and diode clamp (200 V) across the primary or a single 550V Zener clamp from DRAIN to SOURCE can also be used. In all cases care should be taken to minimize the circuit path from the clamp components to the transformer and TinySwitch-II. Thermal Considerations Copper underneath the TinySwitch-II acts not only as a single point ground, but also as a heatsink. The hatched areas shown in Figure17 should be maximized for good heat sinking of TinySwitch-II and the same applies to the output diode. EN/UV pin If a line under-voltage detect resistor is used then the resistor should be mounted as close as possible to the EN/UV pin to minimize noise pick up. The voltage rating of a resistor should be considered for the under-voltage detect (Figure 15: R2, R3) resistors. For 1/4W resistors, the voltage rating is typically 200V continuous, whereas for 1/2W resistors the rating is typically 400V continuous. Y-Capacitor The placement of the Y-capacitor should be directly from the primary bulk capacitor positive rail to the common/return terminal on the secondary side. Such placement will maximize the EMI benefit of the Y-capacitor and avoid problems in common-mode surge testing. Optocoupler It is important to maintain the minimum circuit path from the optocoupler transistor to the TinySwitch-II EN/UV and SOURCE pins to minimize noise coupling. The EN/UV pin connection to the optocoupler should be kept to an absolute minimum (less than 12.7 mm or 0.5 in.), and this connection should be kept away from the DRAIN pin (minimum of 5.1 mm or 0.2 in.). Output Diode For best performance, the area of the loop connecting the secondary winding, the Output Diode and the Output Filter Capacitor, should be minimized. See Figure17 for optimized layout. In addition, sufficient copper area should be provided at the anode and cathode terminals of the diode for adequate heatsinking. Input and Output Filter Capacitors There are constrictions in the traces connected to the input and output filter capacitors. These constrictions are present for two reasons. The first is to force all the high frequency currents to flow through the capacitor (if the trace were wide then it could flow around the capacitor). Secondly, the constrictions minimize the heat transferred from the TinySwitch-II to the input filter capacitor and from the secondary diode to the output filter capacitor. The common/return (the negative output terminal in Figure17) terminal of the output filter capacitor should be connected with a short, low impedance path to the secondary winding. In addition, the common/return output connection B 7/01 11 TNY264/266-268 Safety Spacing Input Filter Capacitor Y1Capacitor + Output Filter Capacitor HV — PRI D S TOP VIEW T r a n s f o r m e r SEC TinySwitch-II Optocoupler CBP BP S EN/UV — DC + Out Maximize hatched copper areas ( ) for optimum heat sinking PI-2707-012901 Figure 17. Recommended Circuit Board Layout for TinySwitch-II with Under-Voltage Lock Out Resistor. should be taken directly from the secondary winding pin and not from the Y-capacitor connection point. PC Board Cleaning Power Integrations does not recommend the use of “no clean” flux. For the most up-to-date information visit the PI Web site at: www.powerint.com 12 B 7/01 TNY264/266-268 ABSOLUTE MAXIMUM RATINGS(1) DRAIN Voltage ....................................... - 0.3 V to 700 V Peak DRAIN Current (TNY264) ...........................400 mA Peak DRAIN Current (TNY266) ...........................560 mA Peak DRAIN Current (TNY267) ...........................720 mA Peak DRAIN Current (TNY268) ...........................880 mA EN/UV Voltage ............................................ - 0.3 V to 9 V EN/UV Current ......................................................100 mA BYPASS Voltage .......................................... -0.3 V to 9 V Storage Temperature ..................................... -65 to 150 °C Operating Junction Temperature(2) ................ -40 to 150 °C Lead Temperature(3) ................................................ 260 °C Notes: 1. All voltages referenced to SOURCE, TA = 25 °C. 2. Normally limited by internal circuitry. 3. 1/16" from case for 5 seconds. THERMAL IMPEDANCE Thermal Impedance: P/G Package: Notes: (θJA) ........ 45 °C/W(2); 35 °C/W(3) 1. Measured on the SOURCE pin close to plastic interface. (θJC)(1) .......................... 11 °C/W 2. Soldered to 0.36 sq. inch (232 mm2), 2oz. (610 gm/m2) copper clad. 3. Soldered to 1 sq. inch (645 mm2), 2oz. (610 gm/m2) copper clad. Parameter Symbol Conditions SOURCE = 0 V; TJ = -40 to 125 °C See Figure 18 (Unless Otherwise Specified) Min Typ Max 124 132 140 Units CONTROL FUNCTIONS TJ = 25 °C See Figure 4 Average Output Frequency fOSC Maximum Duty Cycle DCMAX S1 Open 62 65 68 % EN/UV Pin Turnoff Threshold Current IDIS TJ = -40 °C to 125 °C -300 -240 -170 µA EN/UV Pin Voltage VEN IEN/UV = -125 µA 0.4 1.0 1.5 IEN/UV = 25 µA 1.3 2.3 2.7 VEN/UV = 0 V 320 430 500 TNY264 170 225 270 TNY266 200 265 320 TNY267 240 315 380 TNY268 285 380 460 TNY264 -5.5 -3.3 -1.8 TNY266-268 -7.5 -4.6 -2.5 TNY264 -3.8 -2.0 -1.0 TNY266-268 -4.5 -3.0 -1.5 5.6 5.85 6.15 V 0.80 0.95 1.20 V IS1 DRAIN Supply Current IS2 ICH1 BYPASS Pin Charge Current ICH2 BYPASS Pin Voltage VBP BYPASS Pin Voltage Hysteresis VBPH EN/UV Open (MOSFET Switching) See Note A, B VBP = 0 V, TJ = 25 °C See Note C, D VBP = 4 V, TJ = 25 °C See Note C, D 8 Peak-Peak Jitter See Note C kHz V µA µA mA B 7/01 13 TNY264/266-268 Conditions Parameter Symbol SOURCE = 0 V; TJ = -40 to 125 °C See Figure 18 (Unless Otherwise Specified) Min Typ Max Units 44 49 54 µA CONTROL FUNCTIONS (cont.) EN/UV Pin Line Under-voltage Threshold ILUV TJ = 25 °C CIRCUIT PROTECTION Current Limit ILIMIT TNY264 TJ = 25 °C di/dt = 50 mA/µs See Note E 233 250 267 TNY266 TJ = 25 °C di/dt = 70 mA/µs See Note E 325 350 375 TNY267 TJ = 25 °C di/dt = 90 mA/µs See Note E 419 450 481 TNY268 TJ = 25 °C di/dt = 110 mA/µs See Note E 512 550 588 mA Initial Current Limit IINIT See Figure 21 TJ = 25 °C 0.65 x ILIMIT (MIN) Leading Edge Blanking Time tLEB TJ = 25 °C See Note F 170 Current Limit Delay tILD TJ = 25 °C See Note F, G Thermal Shutdown Temperature 125 Thermal Shutdown Hysteresis mA 215 ns 150 ns 135 150 °C °C 70 OUTPUT TNY264 ID = 25 mA ON-State Resistance RDS(ON) TNY266 ID = 35 mA TNY267 ID = 45 mA TNY268 ID = 55 mA VBP = 6.2 V, OFF-State Leakage IDSS VEN/UV = 0 V, VDS = 560 V, TJ = 125 °C 14 B 7/01 TJ = 25 °C 28 32 TJ = 100 °C 42 48 TJ = 25 °C 14 16 TJ = 100 °C 21 24 TJ = 25 °C 7.8 9.0 TJ = 100 °C 11.7 13.5 TJ = 25 °C 5.2 6.0 TJ = 100 °C 7.8 9.0 TNY264 TNY266 50 TNY267 TNY268 100 Ω µA TNY264/266-268 Conditions Parameter Symbol SOURCE = 0 V; TJ = -40 to 125 °C See Figure 18 (Unless Otherwise Specified) Min Typ Max Units OUTPUT (cont.) Breakdown Voltage BVDSS Rise Time tR Fall Time tF VBP = 6.2 V, VEN/UV = 0 V, IDS = 100 µA, TJ = 25 °C V 700 50 ns 50 ns Measured in a Typical Flyback Converter Application Drain Supply Voltage 50 Output EN/UV Delay tEN/UV Output Disable Setup Time tDST Auto-Restart ON-Time tAR Auto-Restart Duty Cycle DCAR V TJ = 25 °C See Note H µs 10 See Figure 20 0.5 µs 50 ms 5.6 % NOTES: A. Total current consumption is the sum of IS1 and IDSS when EN/UV pin is shorted to ground (MOSFET not switching) and the sum of IS2 and IDSS when EN/UV pin is open (MOSFET switching). B Since the output MOSFET is switching, it is difficult to isolate the switching current from the supply current at the DRAIN. An alternative is to measure the BYPASS pin current at 6.1 V. C. BYPASS pin is not intended for sourcing supply current to external circuitry. D. See typical performance characteristics section for BYPASS pin start-up charging waveform. E. For current limit at other di/dt values, refer to Figure 25. F. This parameter is derived from characterization. G. This parameter is derived from the change in current limit measured at 1X and 4X of the di/dt shown in the ILIMIT specification. H. Auto-restart on time has the same temperature characteristics as the oscillator (inversely proportional to frequency). B 7/01 15 TNY264/266-268 470 Ω 5W S2 470 Ω D EN/UV S1 S S S S BP 2 MΩ 50 V 10 V 150 V 0.1 µF NOTE: This test circuit is not applicable for current limit or output characteristic measurements. PI-2686-101700 Figure 18. TinySwitch-II General Test Circuit. DCMAX t2 (internal signal) t1 tP HV 90% 90% EN/UV DRAIN VOLTAGE t D= 1 t2 tEN/UV VDRAIN 10% 0V t = P 1 fOSC PI-2048-033001 PI-2364-012699 Figure 20. TinySwitch-II Output Enable Timing. PI-2362-052301 DRAIN Current (normalized) Figure 19. TinySwitch-II Duty Cycle Measurement. tLEB (Blanking Time) 1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 IINIT(MIN) ILIMIT(MIN) @ 100 °C 0 0 1 2 3 4 5 Time (µs) Figure 21. Current Limit Envelope. 16 B 7/01 6 7 8 TNY264/266-268 Typical Performance Characteristics 1.0 PI-2680-012301 1.2 1.0 Output Frequency Normalized to 25 °C PI-2213-012301 0.8 0.6 0.4 0.2 0 0.9 -50 -25 0 25 50 -50 75 100 125 150 0.6 0.4 0.2 75 100 125 PI-2697-012301 1.2 1.0 0.8 0.6 TNY264 TNY266 TNY267 TNY268 0.4 0.2 0 Normalized di/dt = 1 50 mA/µs 70 mA/µs 90 mA/µs 110 mA/µs Normalized Current Limit = 1 250 mA 350 mA 450 mA 550 mA 0 -50 0 50 100 150 1 2 Temperature (°C) 3 4 Normalized di/dt Figure 25. Current Limit vs. di/dt. PI-2240-012301 7 6 5 4 3 2 1 300 TCASE=25 °C TCASE=100 °C 250 Drain Current (mA) Figure 24. Current Limit vs. Temperature. BYPASS Pin Voltage (V) 50 1.4 Normalized Current Limit PI-2714-031401 Current Limit (Normalized to 25 °C) TNY264/266 TNY267 TNY268 0.8 25 Figure 23. Frequency vs. Temperature. Figure 22. Breakdown vs. Temperature. 1 0 Junction Temperature (°C) Junction Temperature (°C) 1.2 -25 PI-2221-031401 Breakdown Voltage (Normalized to 25 °C) 1.1 Scaling Factors: TNY264 1.0 TNY266 2.0 TNY267 3.5 TNY268 5.5 200 150 100 50 0 0 0 0.2 0.4 0.6 0.8 Time (ms) Figure 26. Bypass Pin Start-up Waveform. 1.0 0 2 4 6 8 10 Drain Voltage (V) Figure 27. Output Characteristic. B 7/01 17 TNY264/266-268 35 PI-2683-031401 30 Scaling Factors: TNY264 1.0 TNY266 2.0 TNY267 3.5 TNY268 5.5 25 100 Power (mW) Drain Capacitance (pF) 1000 Scaling Factors: TNY264 1.0 TNY266 2.0 TNY267 3.5 TNY268 5.5 10 20 PI-2225-031401 Typical Performance Characteristics (cont.) 15 10 5 1 0 0 100 200 300 400 500 600 0 200 Drain Voltage (V) 400 600 Drain Voltage (V) Figure 29. Drain Capacitance Power. Figure 28. COSS vs. Drain Voltage. PI-2698-012301 Under-Voltage Threshold (Normalized to 25 °C) 1.2 1.0 0.8 0.6 0.4 0.2 0 -50 -25 0 25 50 75 100 125 Junction Temperature (°C) Figure 30. Undervoltage Threshold vs. Temperature. PART ORDERING INFORMATION TinySwitch Product Family Series Number Package Identifier G Plastic Surface Mount DIP P Plastic DIP Package/Lead Options TNY 264 G - TL Blank TL 18 B 7/01 Standard Configurations Tape & Reel, 1 k pcs minimum, G Package only TNY264/266-268 DIP-8B ⊕ D S .004 (.10) Notes: 1. Package dimensions conform to JEDEC specification MS-001-AB (Issue B 7/85) for standard dual-in-line (DIP) package with .300 inch row spacing. 2. Controlling dimensions are inches. Millimeter sizes are shown in parentheses. 3. Dimensions shown do not include mold flash or other protrusions. Mold flash or protrusions shall not exceed .006 (.15) on any side. 4. Pin locations start with Pin 1, and continue counter-clockwise to Pin 8 when viewed from the top. The notch and/or dimple are aids in locating Pin 1. Pin 6 is omitted. 5. Minimum metal to metal spacing at the package body for the omitted lead location is .137 inch (3.48 mm). 6. Lead width measured at package body. 7. Lead spacing measured with the leads constrained to be perpendicular to plane T. -E- .245 (6.22) .255 (6.48) Pin 1 -D- .375 (9.53) .385 (9.78) .128 (3.25) .132 (3.35) .057 (1.45) .063 (1.60) (NOTE 6) 0.15 (.38) MINIMUM -TSEATING PLANE .100 (2.54) BSC .010 (.25) .015 (.38) .125 (3.18) .135 (3.43) .300 (7.62) BSC (NOTE 7) .300 (7.62) .390 (9.91) .048 (1.22) .053 (1.35) .014 (.36) .022 (.56) ⊕ T E D S .010 (.25) M P08B PI-2551-101599 SMD-8B ⊕ D S .004 (.10) -E- .372 (9.45) .388 (9.86) ⊕ E S .010 (.25) .245 (6.22) .255 (6.48) Pin 1 .100 (2.54) (BSC) -D- .375 (9.53) .385 (9.78) .057 (1.45) .063 (1.60) (NOTE 5) .128 (3.25) .132 (3.35) .032 (.81) .037 (.94) .048 (1.22) .053 (1.35) Notes: 1. Controlling dimensions are inches. Millimeter sizes are shown in parentheses. 2. Dimensions shown do not include mold flash or other protrusions. Mold flash or protrusions shall not exceed .006 (.15) on any side. .420 3. Pin locations start with Pin 1, and continue counter-clock .046 .060 .060 .046 Pin 8 when viewed from the top. Pin 6 is omitted. 4. Minimum metal to metal .080 spacing at the package body Pin 1 for the omitted lead location is .137 inch (3.48 mm). .086 5. Lead width measured at .186 package body. .286 6. D and E are referenced Solder Pad Dimensions datums on the package body. Heat Sink is 2 oz. Copper As Big As Possible .004 (.10) .009 (.23) .004 (.10) .012 (.30) .036 (0.91) .044 (1.12) 0°- 8° G08B PI-2546-040501 B 7/01 19 TNY264/266-268 Revision Notes A Date 1) Corrected first page spacing and sentence in description describing innovative design. B 3/01 7/01 2) Corrected Frequency Jitter in Figure 4 and Frequency Jitter in Parameter Table. 3) Added last sentence to Over Temperature Protection section. 4) Clarified detecting when there is no external resistor connected to the EN/UV pin. 5) Corrected Figure 6 and its description in the text. 6) Corrected formatting, grammer and style errors in text and figures. 7) Corrected and moved Worst Case EMI & Efficiency Measurement section 8) Added PC Board Cleaning section. 9) Replaced Figure 21 and SMD-8B Package Drawing. For the latest updates, visit our Web site: www.powerint.com Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability. Power Integrations does not assume any liability arising from the use of any device or circuit described herein, nor does it convey any license under its patent rights or the rights of others. The PI Logo, TOPSwitch, TinySwitch and EcoSmart are registered trademarks of Power Integrations, Inc. ©Copyright 2001, Power Integrations, Inc. WORLD HEADQUARTERS AMERICAS Power Integrations, Inc. 5245 Hellyer Avenue San Jose, CA 95138 USA Main: +1 408-414-9200 Customer Service: Phone: +1 408-414-9665 Fax: +1 408-414-9765 e-mail: [email protected] EUROPE & AFRICA Power Integrations (Europe) Ltd. Centennial Court Easthampstead Road Bracknell Berkshire, RG12 1YQ United Kingdom Phone: +44-1344-462-300 Fax: +44-1344-311-732 e-mail: [email protected] TAIWAN Power Integrations International Holdings, Inc. 17F-3, No. 510 Chung Hsiao E. Rd., Sec. 5, Taipei, Taiwan 110, R.O.C. Phone: +886-2-2727-1221 Fax: +886-2-2727-1223 e-mail: [email protected] CHINA Power Integrations International Holdings, Inc. Rm# 1705, Bao Hua Bldg. 1016 Hua Qiang Bei Lu Shenzhen, Guangdong 518031 China Phone: +86-755-367-5143 Fax: +86-755-377-9610 e-mail: [email protected] KOREA Power Integrations International Holdings, Inc. Rm# 402, Handuk Building 649-4 Yeoksam-Dong, Kangnam-Gu, Seoul, Korea Phone: +82-2-568-7520 Fax: +82-2-568-7474 e-mail: [email protected] JAPAN Power Integrations, K.K. Keihin-Tatemono 1st Bldg. 12-20 Shin-Yokohama 2-Chome Kohoku-ku, Yokohama-shi Kanagawa 222-0033, Japan Phone: +81-45-471-1021 Fax: +81-45-471-3717 e-mail: [email protected] INDIA (Technical Support) Innovatech #1, 8th Main Road Vasanthnagar Bangalore, India 560052 Phone: +91-80-226-6023 Fax: +91-80-228-9727 e-mail: [email protected] APPLICATIONS HOTLINE World Wide +1-408-414-9660 20 B 7/01 APPLICATIONS FAX World Wide +1-408-414-9760