Electronic Components Datasheet Search |
|
MAX6615AEE Datasheet(PDF) 8 Page - Maxim Integrated Products |
|
MAX6615AEE Datasheet(HTML) 8 Page - Maxim Integrated Products |
8 / 20 page ture. The thermistor data in the temperature register(s) gives the voltage across REXT as a fraction of the refer- ence voltage. The LSB of the high byte has a nominal weight of 7.68mV. O OT T Output The OT output asserts when a thermal fault occurs, and can therefore be used as a warning flag to initiate sys- tem shutdown, or to throttle clock frequency. When temperature exceeds the OT temperature threshold and OT is not masked, the OT status register indicates a fault and OT output becomes asserted. If OT for the respective channel is masked off, the OT status register continues to be set, but the OT output does not become asserted. The fault flag and the output can be cleared by reading the OT status register. The OT output can also be cleared by masking the affected channel. If the OT sta- tus bit is cleared, OT reasserts on the next conversion if the temperature still exceeds the OT temperature threshold. PWM Output The PWM_ signals are normally used in one of three ways to control the fan’s speed: 1) PWM_ drives the gate of a MOSFET or the base of a bipolar transistor in series with the fan’s power sup- ply. The Typical Application Circuit shows the PWM_ driving an n-channel MOSFET. In this case, the PWM invert bit (D4 in register 02h) is set to 1. Figure 4 shows PWM_ driving a p-channel MOSFET and the PWM invert bit must be set to zero. 2) PWM_ is converted (using an external circuit) into a DC voltage that is proportional to duty cycle. This duty-cycle-controlled voltage becomes the power supply for the fan. This approach is less efficient than (1), but can result in quieter fan operation. Figure 5 shows an example of a circuit that converts the PWM signal to a DC voltage. Because this circuit produces a full-scale output voltage when PWM = 0V, bit D4 in register 02h should be set to zero. 3) PWM_ directly drives the logic-level PWM speed- control input on a fan that has this type of input. This approach requires fewer external components and combines the efficiency of (1) with the low noise of (2). An example of PWM_ driving a fan with a speed- control input is shown in Figure 6. Bit D4 in register 02h should be set to 1 when this configuration is used. Whenever the fan has to start turning from a motionless state, PWM_ is forced high for 2s. After this spin-up period, the PWM_ duty cycle settles to the predeter- mined value. Whenever spin-up is disabled (bit 2 in the configuration byte = 1) and the fan is off, the duty cycle changes immediately from zero to the nominal value, ignoring the duty-cycle rate-of-change setting. The frequency-select register controls the frequency of the PWM signal. When the PWM signal modulates the power supply of the fan, a low PWM frequency (usually 33Hz) should be used to ensure the circuitry of the Dual-Channel Temperature Monitors and Fan-Speed Controllers with Thermistor Inputs 8 _______________________________________________________________________________________ Table 1. Temperature Data Format (High Byte and Low Byte) HIGH BYTE LOW BYTE TEMPERATURE (°C) BINARY VALUE HEX VALUE BINARY VALUE HEX VALUE 140.0 1000 1100 8Ch 0000 0000 00h 127.0 0111 1111 7Fh 0000 0000 00h 25.375 0001 1001 19h 0110 0000 60h 25.0 0001 1001 19h 0000 0000 00h 0.5 0000 0000 00h 1000 0000 80h 0.0 0000 0000 00h 0000 0000 00h <0 0000 0000 00h 0000 0000 00h VCC PWM 10k Ω 5V P Figure 4. Driving a p-Channel MOSFET for Top-Side PWM Fan Drive |
Similar Part No. - MAX6615AEE |
|
Similar Description - MAX6615AEE |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |