Electronic Components Datasheet Search |
|
UCC3956 Datasheet(PDF) 9 Page - Texas Instruments |
|
UCC3956 Datasheet(HTML) 9 Page - Texas Instruments |
9 / 10 page 9 UCC2956 UCC3956 APPLICATION INFORMATION (cont.) vides a gain of 5, an inverting stage adds a gain of 1.5, and the modulator has a gain of 0.64; adding a fixed gain of 4.8 to the power stage. The current amplifier’s gain be- tween fOSC/10 and fOSC is equal to RF4 divided by the parallel combination of RG1 and RG2 times the resistive divider RG2/(RG1+RG2), simplifying to: GCA = RF4 RG1 RF4 is selected to be 15k, resulting in a 10kHz crossover frequency. Once RF4 is determined, CF3 and CF4 can be selected to give corner frequencies at fOSC/10 and fOSC respectively. CF3 = 1 2 fOSC RF4 π CF4 = 10 2 fOSC RF4 π In the applications circuit, a value of 100pF is used for CF3 and 1.0nF is used for CF4. Figure 4a shows the power stage gain and feedback network gain for the cur- rent loop. Figure 4b shows the total open loop gain and phase. Adding the Voltage Control Loop The voltage loop comes into regulation during the over- charge period of operation. The output of the voltage am- plifier begins to decrease, demanding less current to the battery. With the current loop closed, the power stage gain of the voltage loop is equal to 1/(5*RSENSE) out to the crossover frequency (10kHz). In order to avoid inter- actions with the current loop, the voltage loop will cross unity at 2kHz. The voltage loop is attenuated by the di- vider RG1/(RG1+RG2). A single pole network is added to the voltage amplifier, giving a high gain at DC. Refer- ring to Figure 3, the voltage amplifier gain is equal to the impedance of CF1 divided by RS1. A 2.2nF capacitor will give a total crossover frequency near 2kHz. Figure 5a shows the gain of the power and feedback stages for the voltage loop. Figure 5b shows the total gain and phase of the voltage loop. -60 -40 -20 0 20 40 60 80 10 100 1000 10000 100000 1000000 FREQUENCY POWER STAGE GAIN FEEDBACK GAIN Figure 5a. Voltage Loop Power Stage Gain -150 -100 -50 0 50 100 10 100 1000 10000 100000 1000000 FREQUENCY TOTAL LOOP GAIN TOTAL PHASE Figure 5b. Voltage Loop Total Gain and Phase -80 -60 -40 -20 0 20 40 60 80 100 120 10 100 1000 10000 100000 1000000 FREQUENCY TOTAL LOOP GAIN TOTAL PHASE Figure 4b. Current Loop Total Gain and Phase UNITRODE CORPORATION 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL. (603) 424-2410 • FAX (603) 424-3460 |
Similar Part No. - UCC3956 |
|
Similar Description - UCC3956 |
|
|
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 |