Product overview

This chapter contains an overview of the main features found in nPM1100.

Block diagram

The block diagram illustrates the overall system.

Figure 1. Block diagram
nPM1100 Block diagram

In circuit configurations

The device is configurable for different applications and battery characteristics through input pins.

Static input pins must be configured before power-on reset. Dynamic input pins may be modified during operation under conditions described in references. For the full list of pins, see Pin assignments.

Table 1. In circuit configurations
Pin Function Input type Usage reference

Sets termination voltage

Battery dependent

Static (H/L) Termination voltage (VTERMSET)
ICHG Charge current limit Static (resistor) Charge current limit (ICHG)
ISET VBUS current limit Dynamic (H/L)

VBUS current limit ISET

MODE BUCK PWM mode override Dynamic (H/L) BUCK mode selection (MODE)
VOUTBSET[n] Two pin VOUTB voltage configuration Static (H/L) Output voltage selection (VOUTBSET0, VOUTBSET1)
SHPACT Enables Ship mode Dynamic (H/L)1 Using Ship mode
SHPHLD Disables Ship mode Dynamic (H/L)1 Using Ship mode

1These pins are level and hold-time controlled.

System description

The device has the following core components that are described in detail in the respective chapters.

The system regulator (SYSREG) is a 5 V LDO supplied by VBUS. It generates VINT when enabled. VINT is the internal supply for the device and available on an external pin, VSYS. SYSREG supports a wide operating voltage range on VBUS, tolerates transient voltages up to 20 V, and implements overvoltage protection. SYSREG also implements configurable current limiting from VBUS, and USB port detection. When VBUS is disconnected, SYSREG ensures the device enters Ultra-Low Power mode to minimize quiescent current. Reverse current protection is enabled when VBUS<VBAT. See SYSREG — System regulator for more information and electrical parameters.

The battery charger (CHARGER) is a JEITA compatible linear battery charger for Li-ion/Li-poly batteries. CHARGER controls the charge cycle using a standard Li-ion charge profile. CHARGER implements dynamic power-path management regulating current in and out of the battery, depending on system requirements. Charge current and charge termination voltage can be set with the ICHG and VTERMSET pins respectively. LED drivers for charging indication and charging error indication are implemented in CHARGER. See CHARGER — Battery charger for more information and electrical parameters.

The buck regulator (BUCK) is a step-down DC/DC regulator with PWM and Hysteretic modes with automatic control for optimum efficiency and manual enable of PWM mode to reduce voltage ripple and inductive interference if needed. The output voltage is pin configurable (through VOUTSET0 and VOUTSET1) for different application circuit requirements. BUCK is supplied by VINT (from SYSREG or the battery). See BUCK — Buck regulator for more information and electrical parameters.

The device also features Ship mode, the lowest quiescent current state. It disconnects the battery from the system and reduces the quiescent current of the device to extend battery life when products are in storage. See Using Ship mode and Charging and error LED drivers for more information.

Power-on reset (POR) and brownout reset (BOR)

When one of the following conditions are met, a power-on reset (POR) occurs.

When both of the following conditions are met, a brownout reset (BOR) occurs.

BOR may occur if both supply voltages are below the maximum of the parameter range. BOR occurs if both supply voltages are below the minimum of the parameter range.

The device is held in reset, or System OFF, when both supply voltages VBAT and VBUS are below minimum thresholds.

DPPM — Dynamic power-path management

Dynamic power-path management (DPPM) is a feature that regulates internal voltage (VINT) as system load (ISYS) changes to maintain supply to the application circuit (supplied by the VSYS and VOUTB pins).

CHARGER applies DPPM during charging, after charging completes, or when the VBUS pin is disconnected, to dynamically control current in and out of the battery. See DPPM — Dynamic power-path management.

Using Ship mode

Ship mode isolates the battery, reducing quiescent current.

To enter Ship mode, SHPACT must be set high for a minimum period of tactiveToShip when VBUS is disconnected and SHPHLD held high (VIH). SHPACT has an internal pull-down resistor. SHIPACT can be connected to a microcontroller GPIO (using logic levels in the range VIL and VIH) or to a PCB test pin for activation at the end of production.
Note: VBUS must be discharged to below minimum level VBUSMIN which may require waiting for any capacitive discharge before activating SHPACT.

There are two ways to exit Ship mode. Either connect the USB (VBUS) or set SHPHLD low for a minimum period of tshipToActive. The battery supply (VBAT) is used to hold SHPHLD high through a weak pull-up resistor when Ship mode is enabled. A circuit to pull down SHPHLD is optional (see the Button switch shown in the following figure). If no pull-down circuit is present, Ship mode is exited when VBUS is connected.

If Ship mode is not required, then SHPACT and SHPHLD pins may be tied to AVSS.

Figure 2. A typical configuration for Ship mode

Thermal protection

The device implements thermal regulation based on battery temperature, see Battery thermal protection using NTC thermistor (NTC) and Charger thermal regulation.

In addition to battery thermal protection and charger thermal regulation, a global thermal shutdown based on die temperature is implemented when die temperature exceeds the operating temperature range, see TSD. All device functions are disabled in thermal shutdown. The device functions are re-enabled when the temperature is sufficiently reduced according to a hysteresis TSDHYST.

Battery considerations

The charger can only be used with Li-ion/Li-poly rechargeable batteries.

Battery packs connected to the VBAT pin must contain the following protection circuitry:

  • Overcharge protection
  • Undervoltage protection
  • Overcurrent discharge fuse
  • Thermal fuse to protect from overtemperature (if NTC thermistor is not present)

Charging and error LED drivers

CHARGER controls the CHG and ERR pins, which are used to drive LEDs and signal status to an external circuit.

See Charging indication (CHG) and charging error indication (ERR) for more information.

System electrical parameters

Table 2. System electrical parameters
Symbol Description Min. Typ. Max. Unit
IQSHIP Ship mode quiescent current - 460 - nA
IQBAT Quiescent current, battery operation, no load, MODE = LOW, VBUS disconnected - 800 - nA
TSD Thermal shutdown threshold - 120 - °C
TSDHYST Thermal shutdown hysteresis - 10 - °C
VIH Input HIGH 1.1 - VINT V
VIL Input LOW 0 - 0.4 V
RSHPACT Internal resistance between SHPACT and AVSS   500   kΩ
tactiveToShip Duration SHPACT must be held high to enable Ship mode 200     ms
tshipToActive Duration SHPHLD must be held low to disable Ship mode 200     ms

System efficiency

Described here is the characterization of the power path from the battery supply (VBAT) to the BUCK output (VOUTB) under different battery voltages, output voltages, and load current conditions.

In the following figure, the load current is swept from 1 µA to 150 mA and back to capture mode change hysteresis.

Figure 3. VOUTB = 3.0 V system efficiency, MODE=AUTO
System efficiency plot