Datasheet LTC4000 (Analog Devices) - 8
| Manufacturer | Analog Devices |
| Description | High Voltage High Current Controller for Battery Charging and Power Management |
| Pages / Page | 40 / 8 — pin FuncTions (QFN/SSOP). VM (Pin 1/Pin 25):. ENC (Pin 5/Pin 1):. IBMON … |
| File Format / Size | PDF / 489 Kb |
| Document Language | English |
pin FuncTions (QFN/SSOP). VM (Pin 1/Pin 25):. ENC (Pin 5/Pin 1):. IBMON (Pin 6/Pin 2):. RST (Pin 2/Pin 26):. CX (Pin 7/Pin 3):
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Text Version of Document
LTC4000
pin FuncTions (QFN/SSOP) VM (Pin 1/Pin 25):
Voltage Monitor Input. High impedance
ENC (Pin 5/Pin 1):
Enable Charging Pin. High impedance input to an accurate comparator with a 1.193V threshold digital input pin. Pull this pin above 1.5V to enable charg- (typical). This pin controls the state of the RST output ing and below 0.5V to disable charging. Leaving this pin pin. Connect a resistor divider (RVM1, RVM2) between the open causes the internal 2µA pull-up current to pull the monitored voltage and GND, with the center tap point con- pin to 2.5V (typical). nected to this pin. The falling threshold of the monitored
IBMON (Pin 6/Pin 2):
Battery Charge Current Monitor. The voltage is calculated as follows: voltage on this pin is 20 times (typical) the sense voltage (V V • 1.193V CSP,CSN) across the battery current sense resistor (RCS), VM _RST = RVM1 + RVM2 therefore providing a voltage proportional to the battery RVM2 charge current. Connect an appropriate capacitor to this where RVM2 is the bottom resistor between the VM pin pin to obtain a voltage representation of the time-average and GND. Tie to the BIAS pin if voltage monitoring func- battery charge current. Short this pin to GND to disable tion is not used. charge current limit feature.
RST (Pin 2/Pin 26):
High Voltage Open Drain Reset Output.
CX (Pin 7/Pin 3):
Charge Current Termination Pro- When the voltage at the VM pin is below 1.193V, this status gramming. Connect the charge current termination pro- pin is pulled low. When driven low, this pin can disable gramming resistor (R a DC/DC converter when connected to the converter’s CX) to this pin. This pin is a high impedance input to a comparator and sources 5μA of enable pin. This pin can also drive an LED to provide a current. When the voltage on this pin is greater than the visual status indicator of a monitored voltage. Short this charge current monitor voltage (V pin to GND when not used. IBMON), the CHRG pin turns high impedance indicating that the CX threshold is
IIMON (Pin 3/Pin 27):
Input Current Monitor. The voltage reached. When this occurs, the charge current is imme- on this pin is 20 times (typical) the sense voltage (VIN,CLN) diately terminated if the TMR pin is shorted to the BIAS across the input current sense resistor(RIS), therefore pin, otherwise charging continues until the charge termi- providing a voltage proportional to the input current. nation timer expires. The charge current termination value Connect an appropriate capacitor to this pin to obtain a is determined using the following formula: voltage representation of the time-average input current. Short this pin to GND to disable input current limit feature. 0.25µA • R ( )−0.5mV I CX C/X =
IL (Pin 4/Pin 28):
Input Current Limit Programming. Con- RCS nect the input current programming resistor (RIL) to this Where R pin. This pin sources 50µA of current. The regulation loop CS is the sense resistor connected to the CSP and the CSN pins. Note that if R compares the voltage on this pin with the input current CX = RCL ≤ 19.1kΩ, where R monitor voltage (V CL is the charge current programming resistor, then the IIMON), and drives the ITH pin accord- charge current termination value is one tenth the full charge ingly to ensure that the programmed input current limit is current, more familiarly known as C/10. Short this pin to not exceeded. The input current limit is determined using GND to disable CX termination. the following formula:
CL (Pin 8/Pin 4):
Charge Current Limit Programming. Con- I nect the charge current programming resistor (R ILIM = 2.5µA • RIL CL) to this RIS pin. This pin sources 50µA of current. The regulation loop compares the voltage on this pin with the charge current where RIS is the sense resistor connected to the IN and monitor voltage (VIBMON), and drives the ITH pin accord- the CLN pins. Leave the pin open for the maximum input ingly to ensure that the programmed charge current limit current limit of 50mV/RIS. 4000fb 8 For more information www.linear.com/LTC4000 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
pin FuncTions (QFN/SSOP) VM (Pin 1/Pin 25):
Voltage Monitor Input. High impedance
ENC (Pin 5/Pin 1):
Enable Charging Pin. High impedance input to an accurate comparator with a 1.193V threshold digital input pin. Pull this pin above 1.5V to enable charg- (typical). This pin controls the state of the RST output ing and below 0.5V to disable charging. Leaving this pin pin. Connect a resistor divider (RVM1, RVM2) between the open causes the internal 2µA pull-up current to pull the monitored voltage and GND, with the center tap point con- pin to 2.5V (typical). nected to this pin. The falling threshold of the monitored
IBMON (Pin 6/Pin 2):
Battery Charge Current Monitor. The voltage is calculated as follows: voltage on this pin is 20 times (typical) the sense voltage (V V • 1.193V CSP,CSN) across the battery current sense resistor (RCS), VM _RST = RVM1 + RVM2 therefore providing a voltage proportional to the battery RVM2 charge current. Connect an appropriate capacitor to this where RVM2 is the bottom resistor between the VM pin pin to obtain a voltage representation of the time-average and GND. Tie to the BIAS pin if voltage monitoring func- battery charge current. Short this pin to GND to disable tion is not used. charge current limit feature.
RST (Pin 2/Pin 26):
High Voltage Open Drain Reset Output.
CX (Pin 7/Pin 3):
Charge Current Termination Pro- When the voltage at the VM pin is below 1.193V, this status gramming. Connect the charge current termination pro- pin is pulled low. When driven low, this pin can disable gramming resistor (R a DC/DC converter when connected to the converter’s CX) to this pin. This pin is a high impedance input to a comparator and sources 5μA of enable pin. This pin can also drive an LED to provide a current. When the voltage on this pin is greater than the visual status indicator of a monitored voltage. Short this charge current monitor voltage (V pin to GND when not used. IBMON), the CHRG pin turns high impedance indicating that the CX threshold is
IIMON (Pin 3/Pin 27):
Input Current Monitor. The voltage reached. When this occurs, the charge current is imme- on this pin is 20 times (typical) the sense voltage (VIN,CLN) diately terminated if the TMR pin is shorted to the BIAS across the input current sense resistor(RIS), therefore pin, otherwise charging continues until the charge termi- providing a voltage proportional to the input current. nation timer expires. The charge current termination value Connect an appropriate capacitor to this pin to obtain a is determined using the following formula: voltage representation of the time-average input current. Short this pin to GND to disable input current limit feature. 0.25µA • R ( )−0.5mV I CX C/X =
IL (Pin 4/Pin 28):
Input Current Limit Programming. Con- RCS nect the input current programming resistor (RIL) to this Where R pin. This pin sources 50µA of current. The regulation loop CS is the sense resistor connected to the CSP and the CSN pins. Note that if R compares the voltage on this pin with the input current CX = RCL ≤ 19.1kΩ, where R monitor voltage (V CL is the charge current programming resistor, then the IIMON), and drives the ITH pin accord- charge current termination value is one tenth the full charge ingly to ensure that the programmed input current limit is current, more familiarly known as C/10. Short this pin to not exceeded. The input current limit is determined using GND to disable CX termination. the following formula:
CL (Pin 8/Pin 4):
Charge Current Limit Programming. Con- I nect the charge current programming resistor (R ILIM = 2.5µA • RIL CL) to this RIS pin. This pin sources 50µA of current. The regulation loop compares the voltage on this pin with the charge current where RIS is the sense resistor connected to the IN and monitor voltage (VIBMON), and drives the ITH pin accord- the CLN pins. Leave the pin open for the maximum input ingly to ensure that the programmed charge current limit current limit of 50mV/RIS. 4000fb 8 For more information www.linear.com/LTC4000 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
