TNY253/254/255 TinySwitch Family Energy Efficient, Low Power Off-line Switchers Product Highlights Lowest Cost, Low Power Switcher Solution + + Lower cost than RCC, discrete PWM and other integrat- DC ed/hybrid solutions Output Cost effective replacement for bulky linear adapters Lowest component count TinySwitch Wide-Range Simple ON/OFF control no loop compensation devices D High-Voltage EN No bias winding simpler, lower cost transformer DC Input BP Allows simple RC type EMI filter for up to 2 W from S universal input or 4 W from 115 VAC input Extremely Energy Efficient PI-2178-022699 Consumes only 30/60 mW at 115/230 VAC with no load Meets Blue Angel, Energy Star, Energy 2000 and 200 mW Figure 1. Typical Standby Application. European cell phone requirements for standby Saves 1 to 4 per year in energy costs (at 0.12/kWHr) TinySwitch Selection Guide compared to bulky linear adapters Ideal for cellular phone chargers, standby power supplies for Recommended Range PC, TV and VCR, utility meters, and cordless phones. for Lowest System Cost* ORDER PART PACKAGE 230 VAC or High Performance at Low Cost 85-265 NUMBER 115 VAC High-voltage powered ideal for charger applications VAC w/Doubler Very high loop bandwidth provides excellent transient TNY253P response and fast turn on with practically no overshoot DIP-8 0-4 W 0-2 W Current limit operation rejects line frequency ripple TNY253G SMD-8 Glitch free output when input is removed TNY254P DIP-8 Built-in current limit and thermal protection 2-5 W 1-4 W 44 kHz operation (TNY253/4) with snubber clamp TNY254G SMD-8 reduces EMI and video noise in TVs and VCRs TNY255P DIP-8 Operates with optocoupler or bias winding feedback 4-10 W 3.5-6.5 W TNY255G SMD-8 Description Table 1. *Please refer to the Key Application Considerations section for details. The TinySwitch family uses a breakthrough design to provide the lowest cost, high efficiency , off-line switcher solution in The TNY253 and TNY254 switch at 44 kHz to minimize EMI the 0 to 10 W range. These devices integrate a 700 V power and to allow a simple snubber clamp to limit DRAIN spike MOSFET, oscillator, high-voltage switched current source, voltage. At the same time, they allow use of low cost EE16 core current limit and thermal shutdown circuitry. They start-up transformers to deliver up to 5 W. The TNY253 is identical to and run on power derived from the DRAIN voltage, eliminat- TNY254 except for its lower current limit, which reduces output ing the need for a transformer bias winding and the associated short-circuit current for applications under 2.5 W. TNY255 circuitry. And yet, they consume only about 80 mW at no load, uses higher switching rate of 130 kHz to deliver up to 10 W from 265 VAC input. A simple ON/OFF control scheme also from the same low cost EE16 core for applications such as PC eliminates the need for loop compensation. standby supply. An EE13 or EF13 core with safety spaced bobbin can be used for applications under 2.5 W. Absence of a bias winding eliminates the need for taping/margins in most applications, when triple insulated wire is used for the secondary. This simplifies the transformer construction and reduces cost. February 2012TNY253/254/255 REGULATOR DRAIN BYPASS 5.8 V UNDERVOLTAGE + 5.8 V V - I 5.1 V LIMIT OSCILLATOR CLOCK 50 A DC MAX THERMAL SHUTDOWN S Q R Q LEADING 1.5 V + V TH EDGE BLANKING ENABLE SOURCE PI-2197-061898 Figure 2. Functional Block Diagram. 1 8 BYPASS SOURCE Pin Functional Description SOURCE 2 7 SOURCE DRAIN (D) Pin: Power MOSFET drain connection. Provides internal operating SOURCE 3 6 SOURCE current for both start-up and steady-state operation. 4 5 ENABLE DRAIN BYPASS (BP) Pin: Connection point for an external bypass capacitor for the inter- P Package (DIP-8) G Package (SMD-8) nally generated 5.8 V supply. Bypass pin is not intended for PI-2199-031501 sourcing supply current to external circuitry. Figure 3. Pin Configuration. ENABLE (EN) Pin: Hysteretic Over Temperature Protection, Current Limit circuit, The power MOSFET switching can be terminated by pulling Leading Edge Blanking, and a 700 V power MOSFET. Figure this pin low. The I-V characteristic of this pin is equivalent to 2 shows a functional block diagram with the most important a voltage source of approximately 1.5 V with a source current features. clamp of 50 A. Oscillator SOURCE (S) Pin: The oscillator frequency is internally set at 44 kHz (130 kHz Power MOSFET source connection. Primary return. for the TNY255). The two signals of interest are the Maxi- mum Duty Cycle signal (D ) which runs at typically 67% MAX TinySwitch Functional Description duty cycle and the Clock signal that indicates the beginning of each cycle. When cycles are skipped (see below), the oscilla- TinySwitch is intended for low power off-line applications. It tor frequency doubles (except for TNY255 which remains at combines a high-voltage power MOSFET switch with a power 130 kHz). This increases the sampling rate at the ENABLE supply controller in one device. Unlike a conventional PWM pin for faster loop response. (Pulse Width Modulator) controller, the TinySwitch uses a simple ON/OFF control to regulate the output voltage. Enable (Sense and Logic) The ENABLE pin circuit has a source follower input stage set The TinySwitch controller consists of an Oscillator, Enable at 1.5 V. The input current is clamped by a current source set (Sense and Logic) circuit, 5.8 V Regulator, Undervoltage circuit, at 50 A with 10 A hysteresis. The output of the enable sense Rev E 2 02/12 - +