![]() |
Electronic Components Datasheet Search |
|
ISL6552 Datasheet(PDF) 8 Page - Renesas Technology Corp |
|
|
ISL6552 Datasheet(HTML) 8 Page - Renesas Technology Corp |
8 / 18 page ![]() ISL6552 FN4918 Rev 2.00 Page 8 of 18 July 2004 Operation Figure 1 shows a simplified diagram of the voltage regulation and current control loops. Both voltage and current feedback are used to precisely regulate voltage and tightly control output currents, IL1 and IL2, of the two power channels. The voltage loop comprises the error amplifier, comparators, gate drivers and output MOSFETs. The error amplifier is essentially connected as a voltage follower that has as an input, the programmable reference DAC and an output that is the CORE voltage. Voltage Loop Feedback from the CORE voltage is applied via resistor RIN to the inverting input of the error amplifier. This signal can drive the error amplifier output either high or low, depending upon the CORE voltage. Low CORE voltage makes the amplifier output move towards a higher output voltage level. Amplifier output voltage is applied to the positive inputs of the comparators via the correction summing networks. Out-of-phase sawtooth signals are applied to the two comparators inverting inputs. Increasing error amplifier voltage results in increased comparator output duty cycle. This increased duty cycle signal is passed through the PWM circuit with no phase reversal and on to the HIP6601, again with no phase reversal for gate drive to the upper MOSFETs, Q1 and Q3. Increased duty cycle or ON time for the MOSFET transistors results in increased output voltage to compensate for the low output voltage sensed. Current Loop The current control loop works in a similar fashion to the voltage control loop, but with current control information applied individually to each channel’s comparator. The information used for this control is the voltage that is developed across rDS(ON) of each lower MOSFET, Q2 and Q4, when they are conducting. A single resistor converts and scales the voltage across the MOSFETs to a current that is applied to the current sensing circuit within the ISL6552. Output from these sensing circuits is applied to the current averaging circuit. Each PWM channel receives the difference current signal from the summing circuit that compares the average sensed current to the individual channel current. When a power channel’s current is greater than the average current, the signal applied via the summing correction circuit to the comparator, reduces the CURRENT SENSING COMPARATOR PWM CIRCUIT + RISEN1 + CORRECTION ERROR AMPLIFIER FB REFERENCE ISEN1 RIN VCORE Q3 Q4 L2 PHASE PWM1 IL2 DAC ISL6552 COUT RLOAD VIN HIP6601 - Q1 Q2 L1 PHASE IL1 VIN HIP6601 CURRENT SENSING COMPARATOR PWM CIRCUIT CORRECTION PWM2 - I AVERAGE + + - PROGRAMMABLE RISEN2 ISEN2 - CURRENT AVERAGING FIGURE 1. SIMPLIFIED BLOCK DIAGRAM OF THE ISL6552 VOLTAGE AND CURRENT CONTROL LOOPS FOR A TWO POWER CHANNEL REGULATOR + - + - + - |
Similar Part No. - ISL6552 |
|
Similar Description - ISL6552 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | 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 |