Electronic Components Datasheet Search |
|
REG711 Datasheet(PDF) 7 Page - Texas Instruments |
|
REG711 Datasheet(HTML) 7 Page - Texas Instruments |
7 / 10 page REG711 7 SBVS027A THEORY OF OPERATION The REG711 regulated charge pump provides a regulated output voltage for input voltages ranging from less than the output to greater than the output. This is accomplished by automatic mode switching within the device. When the input voltage is greater than the required output, the unit functions as a variable pulse-width switch-mode regulator. This opera- tion is shown in Figure 1. Transistors Q1 and Q3 are held off, Q4 is on, and Q2 is switched as needed to maintain a regulated output voltage. A conversion clock of 50% duty cycle is generated. During the first half cycle the FET switches are configured as shown in Figure 2A, and CPUMP charges to VIN. During the second half cycle the FET switches are configured as shown in Figure 2B, and the voltage on CPUMP is added to VIN. The output voltage is regulated by skipping clock cycles as necessary. PEAK CURRENT REDUCTION In normal operation, the charging of the pump and output capacitors usually leads to relatively high peak input cur- rents which can be much higher than that of the average load current. The regulator incorporates circuitry to limit the input peak current, lowering the total EMI production of the device and lowering output voltage ripple and input current ripple. Input capacitor (CIN) supplies most of the charge required by input current peaks. PROTECTION The regulator has thermal shutdown circuitry that protects it from damage caused by overload conditions. The thermal protection circuitry disables the output when the junction temperature reaches approximately 160 °C, allowing the de- vice to cool. When the junction temperature cools to ap- proximately 140 °C, the output circuitry is automatically re- enabled. Continuously running the regulator into thermal shutdown can degrade reliability. The regulator also pro- vides current limit to protect itself and the load. SHUTDOWN MODE A control pin on the regulator can be used to place the device into an energy-saving shutdown mode. In this mode, the output is disconnected from the input as long as VIN is greater than or equal to minimum VIN and the input quies- cent current is reduced to 2 µA maximum. FIGURE 1. Simplified Schematic of the REG711 Operating in the Step-Down Mode. When the input voltage is less than the required output voltage, the device switched to a step-up or boost mode of operation, as shown in Figure 2. FIGURE 2. Simplified Schematic of the REG711 Operating in the Step-Up or Boost Mode. C PUMP C IN C OUT V OUT V IN Q 1 Q 3 Q 2 Q 4 OFF OFF SWITCHED ON Step-Down (Buck) Mode C PUMP C IN C OUT V OUT V IN Q 1 Q 3 Q 2 Q 4 OFF ON ON OFF Step-Up (Boost) Mode + – (A) C PUMP C IN C OUT V OUT V IN Q 1 Q 3 Q 2 Q 4 ON OFF OFF ON + – (B) |
Similar Part No. - REG711 |
|
Similar Description - REG711 |
|
|
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 |