TC653

TC652/TC653 Integrated Temperature Sensor & Brushless DC Fan Controller with FanSense™ Detect & Over-Temperature Features • Integrated Temperature Sensing and Multi-speed Fan Control • FanSense™ Fan Fault Detect Circuitry • Built-in Over-Temperature Alert (TOVER) • Temperature Proportional Fan Speed Control for Acoustic Noise Reduction and Longer Fan Life • Pulse Width Modulation Output Drive for Cost and Power Savings • Solid-State Temperature Sensing • ±1°C (Typical) Accuracy from 25°C to +70°C • 2.8V – 5.5V Operating Range • TC653 includes Auto Fan Shutdown • Low Operating Current: 50µA (Typical) Package Type MSOP VDD 1 FAULT 2 SHDN 3 GND 4 8 PWM TC652 TC653 7 GND 6 TOVER 5 SENSE General Description The TC652/TC653 are integrated temperature sensors and brushless DC fan speed controllers with FanSense™ technology. The TC652/TC653 measure their junction temperature and control the speed of the fan based on that temperature, making them especially suited for applications in modern electronic equipment. The FanSense™ Fan Fault detect circuitry eliminates the need for a more expensive 3-wire fan. Temperature data is converted from the on-chip thermal sensing element and translated into a fractional fan speed from 40% to 100%. A temperature selection guide in the data sheet is used to choose the low and high temperature limits to control the fan. The TC652/TC653 also include a single trip point over temperature alert (TOVER) that eliminates the need for additional temperature sensors. In addition, the TC653 includes an auto fan shutdown function for additional power savings. The TC652/TC653 are easy to use, require no software overhead and are therefore the ideal choice for implementing thermal management in a variety of systems. Applications • • • • • • Thermal Protection For Personal Computers Digital Set-Top Boxes Notebook Computers Data Communications Power Supplies Projectors Related Literature • Application Note: AN771 Device Selection Table Part Number TC652XXVUA TC653XXVUA Package 8-Pin MSOP 8-Pin MSOP Temperature Range -40°C to +125°C -40°C to +125°C X A B C D E F G Temperature 25 30 35 40 45 50 55 The "X" denotes a suffix for temperature threshold settings. Contact factory for other temperature ranges. 2002 Microchip Technology Inc. DS21453B-page 1 © TC652/TC653 Typical Application Diagram +12V DC Fan 300mA Max. 1k 1 VDD 2 FAULT 3 SHDN 4 GND PWM 8 GND 7 TOVER 6 SENSE 5 CSENSE GND SHDN Control Fan Fault Alert µController Over-Temp Alert RSENSE 2Ω FanSense™ 0.01µF +5V VDD TC652 TC653 © DS21453B-page 2 2002 Microchip Technology Inc. TC652/TC653 1.0 ELECTRICAL CHARACTERISTICS *Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions above those indicated in the operation sections of the specifications is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Absolute Maximum Ratings* Input Voltage (VDD to GND) ................................... +6V Output Voltage (OUT to GND) ................................. 6V Voltage On Any Pin ....... (GND – 0.3V) to (VDD + 0.3V) Package Thermal Resistance (θJA ) ........... 250°C/W Operating Temperature Range ......... -40°C to +125°C Storage Temperature ......................... -65°C to +150°C TC652/TC653 ELECTRICAL SPECIFICATIONS Electrical Characteristics: VDD = 2.8V to 5.5V, SHDN = VDD, TA = -40°C to 125°C unless otherwise specified. Symbol VDD IDD SHDN Input VIH VIL PWM Output VOL VOH tR tF fOUT tSTARTUP VTH (SENSE) PWM Output Low Voltage PWM Output High Voltage PWM Rise Time PWM Fall Time PWM Frequency Start-up Time Sense Input — VDD – 0.5 — — 10 — — — — 10 10 15 32/fOUT 70 0.3 — — — — — — V V µsec µsec Hz sec mV VDD Rises from GND, or SHDN Released Sense Input Threshold Voltage with Repect to Ground ISINK = 1mA ISOURCE = 5mA IOH = 5mA, 1nF from PWM to GND IOL = 1mA, 1nF from PWM to GND SHDN Input High Threshold SHDN Input Low Threshold 65 — — — — 15 %VDD %VDD Parameter Supply Voltage Supply Current Min 2.8 — Typ. — 50 Max 5.5 90 Units V µA PWM, FAULT, TOVER are open Test Conditions Temperature Accuracy TH ACC (TH –TL) ACC THYST FAULT Output VHIGH VLOW tmp TOVER Output VHIGH VLOW TOVER Note ACC High Temperature Accuracy Temp. Range Accuracy Auto-shutdown Hysteresis TH - 3 -1.0 -2.5 — TH — — (TH – TL)/5 TH + 3 +1.0 +2.5 — °C °C °C °C Note 1 (TH – TL) ≤ 20°C (TH – TL) ≥ 20°C TC653 Only FAULT Output High Voltage FAULT Output Low Voltage Missing Pulse Detector Time-out VDD – 0.5 — — — — — — 0.4 32/fOUT V V Sec ISOURCE = 1.2mA ISINK = 2.5mA TOVER Output High Voltage TOVER Output Low Voltage Absolute Accuracy Trip Point Hysteresis Transition from 90% to 100% Duty Cycle. VDD – 0.5 — — — — — TH + 10 5 — 0.4 — — V V °C °C ISOURCE = 1.2mA ISINK = 2.5mA At Trip Point TOVER HYST 1: 2002 Microchip Technology Inc. DS21453B-page 3 © TC652/TC653 2.0 PIN DESCRIPTIONS The descriptions of the pins are listed in Table 2-1. TABLE 2-1: Pin No. (8-Pin MSOP) 1 2 PIN FUNCTION TABLE Symbol VDD FAULT Description Power Supply Input. May be independent of fan power supply. Fan Fault Alert, Active-Low Output. FAULT goes low to indicate a fan FAULT condition. When FAULT occurs, the device is latched in Shutdown mode with PWM low. Toggling the SHDN pin or cycling the VDD will release the part and fan from shutdown. FAULT will unconditionally remain high during shutdown. Fan Shutdown, Active-Low Input. During Shutdown mode the chip still monitors temperature and TOVER is low if temperature rises above factory set point. Ground return for all TC652/TC653 functions. Detect Fan Pulses Input. Pulses are detected at this pin as fan rotation chops the current through the sense resistor, RSENSE. The absence of pulses indicates a Fan Fault. Over-Temperature Alert, Active-Low Output. Ground. PWM Fan Drive Output. Pulse width modulated rail-to-rail logic output. Nominal Frequency is 15Hz. 3 4 5 6 7 8 SHDN GND SENSE TOVER GND PWM © DS21453B-page 4 2002 Microchip Technology Inc. TC652/TC653 3.0 DETAILED DESCRIPTION TABLE 3-2: The TC652/TC653 acquire and convert their junction temperature (TJ) information from an on-chip solid state sensor with a typical accuracy of ±1°C. The temperature data is digitally stored in an internal register. The register is compared with pre-defined threshold values. The six threshold values are equally distributed over a pre-defined range of temperatures (See Table 3-1 and Table 3-2). The TC652/TC653 control the speed of a DC brushless fan using a fractional speed control scheme. The output stage requires only a 2N2222-type small-signal BJT for fans up to 300mA. For larger current fans (up to 1 Amp) a logic-level N-channel MOSFET may be used. In addition to controlling the speed of the fan, the TC652/ TC653 include an on-chip over-temperature alarm (TOVER) that gives a low-true signal when the temperature of the chip exceeds TH by 10°C. This feature eliminates the need for a separate temperature sensor for over-temperature monitoring. In normal fan operation, a pulse-train is present at SENSE, Pin 5. A Missing Pulse Detector monitors this pin during fan operation (FanSense™ technology). A stalled, open, or unconnected fan causes the TC652/ TC653 to trigger its Start-up Timer once. If the FAULT persists, the FAULT output goes low, and the device is latched in its Shutdown mode. To release the fan from shutdown, toggle the SHDN or VDD pin. TEMPERATURE RANGE DEFINITION FOR TC653 (AUTO-SHUTDOWN MODE) PWM Duty Cycle “OFF” 50% 60% 70% 80% 90% 100% 100% with Over-Temp Alert (TOVER = L) Temperature (T = TJ) T < TL TL< = T < T1 T1 < = T < T2 T2 < =T < T3 T3 < =T < T4 T4 < = T < TH TH < = T < TOV TOV < = T Note: The temperature regions defined by the six temperature thresholds are pre-defined in the TC650/651 by means of trimming. Once a TL and TH are programmed, the T1 - T4 thresholds are automatically equally spaced between TL and TH . FIGURE 3-1: VDD FUNCTIONAL BLOCK DIAGRAM TOVER V+ SHDN Duty Cycle Logic Control Temperature Set Point and Trim Range PWM TABLE 3-1: TEMPERATURE RANGE DEFINITION FOR TC652 (MINIMUM-SPEED MODE) PWM Duty Cycle 40% 50% 60% 70% 80% 90% 100% 100% with Over-Temp Alert (TOVER = L) AD Converter Oscillator Temperature (T = TJ) T < TL TL< = T < T1 T1 < = T < T2 T2 < = T