Electronic Components Datasheet Search |
|
NIS5452 Datasheet(PDF) 6 Page - ON Semiconductor |
|
NIS5452 Datasheet(HTML) 6 Page - ON Semiconductor |
6 / 9 page NIS5452 Series www.onsemi.com 6 Figure 10. Common Thermal Shutdown + 5 V GND LOAD Enable 11 8 NIS5452 VIN VOUT Enable/Fault GND 5 10 3 4 2 1 dV /dt RLIMIT 9 ILimit 7 + 12 V LOAD 11 3 NIS5232 VIN VOUT Enable/Fault GND 10 1 8 9 7 6 dV /dt 2 ILimit 4 RLIMIT APPLICATION INFORMATION Basic Operation This device is a self−protected, resettable, electronic fuse. It contains circuits to monitor the input voltage, output voltage, output current and die temperature. On application of the input voltage, the device will apply the input voltage to the load based on the restrictions of the controlling circuits. The dv/dt of the output voltage will be controlled by the internal dv/dt circuit. The output voltage will slew from 0 V to the rated output voltage in 1.4 ms, unless additional capacitance is added to the dv/dt pin. The device will remain on as long as the temperature does not exceed the 175 °C limit that is programmed into the chip. The current limit circuit does not shut down the part but will reduce the conductivity of the FET to maintain a constant current at the internally set current limit level. The input overvoltage clamp also does not shutdown the part, but will limit the output voltage to the Vout−clamp value in the event that the input exceeds that level. An internal charge pump provides bias for the gate voltage of the internal n−channel power FET and also for the current limit circuit. The remainder of the control circuitry operates between the input voltage (VCC) and ground. Application Information It is recommended to connect an input decoupling capacitor and an output filtering capacitor to the device to attenuate the power supply noise and the possible voltage spikes caused by inductive loads. The values of these capacitors depend on the characteristics of the power supply and the inductance observed by the device at its input and output, however, minimum values of 1 mF for the input capacitor and 22 mF for the output capacitor are recommended for most applications. Power Limit Refer to Application Note AND9042/D for ILIMSE limitations. Current Limit The current limit circuit uses a SENSEFET along with a reference and amplifier to control the peak current in the device. The SENSEFET allows for a small fraction of the load current to be measured, which has the advantage of reducing the losses in the sense resistor as well as increasing the value and decreasing the power rating of the sense resistor. Sense resistors are typically in the tens of ohms range with power ratings of several milliwatts making them very inexpensive chip resistors. The current limit circuit has two limiting values, one for overload events which are defined as the mode of operation in which the gate is high and the FET is fully enhanced. The short circuit mode of operation occurs when the device is actively limiting the current and the gate is at an intermediate level. For a more detailed description of this circuit please refer to application note AND8140. There are two methods of biasing the current limit circuit for this device. They are shown in the two application figures. Direct current sensing connects the sense resistor between the current limit pin and the load. This method includes the bond wire resistance in the current limit circuit. This resistance has an impact on the current limit levels for a given resistor and may vary slightly depending on the impedance between the sense resistor and the source pins. The on resistance of the device will be slightly lower in this configuration since all five source pins are connected in parallel and therefore, the effective bond wire resistance is one fifth of the resistance for any given pin. The other method is Kelvin sensing. This method uses one of the source pins as the connection for the current sense resistor. This connection senses the voltage on the die and therefore any bond wire resistance and external impedance on the board have no effect on the current limit levels. In this configuration the on resistance is slightly increased relative to the direct sense method since only four of the source pins are used for power. |
Similar Part No. - NIS5452_16 |
|
Similar Description - NIS5452_16 |
|
|
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 |