Electronic Components Datasheet Search |
|
UCC27324PE4 Datasheet(PDF) 11 Page - Texas Instruments |
|
|
UCC27324PE4 Datasheet(HTML) 11 Page - Texas Instruments |
11 / 28 page P 0.432 W I 0.036 A V 12 V = = = UCC27323, UCC27324, UCC27325 UCC37323, UCC37324, UCC37325 www.ti.com SLUS492H – JUNE 2001 – REVISED MAY 2013 VDD Although quiescent VDD current is very low, total supply current will be higher, depending on OUTA and OUTB current and the programmed oscillator frequency. Total VDD current is the sum of quiescent VDD current and the average OUT current. Knowing the operating frequency and the MOSFET gate charge (Qg), average OUT current is calculated from Equation 1. IOUT = Qg × f where • f is frequency (1) For the best high-speed circuit performance, two VDD bypass capacitors are recommended tp prevent noise problems. The use of surface mount components is highly recommended. A 0.1- μF ceramic capacitor must be located closest to the VDD to ground connection. In addition, a larger capacitor (such as 1- μF) with relatively low ESR must be connected in parallel, to help deliver the high current peaks to the load. The parallel combination of capacitors must present a low impedance characteristic for the expected current levels in the driver application. Drive Current and Power Requirements The UCC37323/4/5 family of drivers are capable of delivering 4-A of current to a MOSFET gate for a period of several-hundred nanoseconds. High peak current is required to turn the device ON quickly. Then, to turn the device OFF, the driver is required to sink a similar amount of current to ground which repeats at the operating frequency of the power device. A MOSFET is used in this discussion because it is the most common type of switching device used in high frequency power conversion equipment. References 1 and 2 discuss the current required to drive a power MOSFET and other capacitive-input switching devices. Reference 2 includes information on the previous generation of bipolar IC gate drivers (see References). When a driver IC is tested with a discrete, capacitive load calculating the power that is required from the bias supply is fairly simple. The energy that must be transferred from the bias supply to charge the capacitor is given by Equation 2. E = ½CV 2 where • C is the load capacitor • V is the bias voltage feeding the driver (2) There is an equal amount of energy transferred to ground when the capacitor is discharged. This leads to a power loss given by Equation 3. P = 2 × ½CV 2f where • f is the switching frequency (3) This power is dissipated in the resistive elements of the circuit. Thus, with no external resistor between the driver and gate, this power is dissipated inside the driver. Half of the total power is dissipated when the capacitor is charged, and the other half is dissipated when the capacitor is discharged. An actual example using the conditions of the previous gate drive waveform helps to clarify this. With VDD = 12 V, CLOAD = 10 nF, and f = 300 kHz, the power loss is calculated with Equation 4. P = 10 nF × (12) 2 × (300 kHz) = 0.432 W (4) With a 12-V supply, this equates to a current of (see Equation 5): (5) The actual current measured from the supply is 0.037 A, and is very close to the predicted value. But, the IDD current that is due to the IC internal consumption must be considered. With no load the IC current draw is 0.0027 A. Under this condition the output rise and fall times are faster than with a load, which could lead to an almost insignificant, yet measurable current due to cross-conduction in the output stages of the driver. However, these small current differences are buried in the high frequency switching spikes, and are beyond the measurement capabilities of a basic lab setup. The measured current with 10-nF load is reasonably close to that expected. Copyright © 2001–2013, Texas Instruments Incorporated Submit Documentation Feedback 11 Product Folder Links: UCC27323 UCC27324 UCC27325 UCC37323 UCC37324 UCC37325 |
Similar Part No. - UCC27324PE4 |
|
Similar Description - UCC27324PE4 |
|
|
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 |