SLVAF89 November   2021 TLV61046A , TLV61048 , TPS61040 , TPS61041 , TPS61045 , TPS61046 , TPS61085 , TPS61086 , TPS61088 , TPS61089 , TPS61096A , TPS61170 , TPS61175 , TPS61178 , TPS61288

 

  1.   Trademarks
  2. 1Introduction
  3. 2Requirements of External Bias for Boost Converters
  4. 3Applicable Devices List and Test Results
  5. 4Application Cases
  6. 5Summary
  7. 6References

3 Applicable Devices List and Test Results

According to the previously-analyzed requirements, the middle-voltage boost converters that support external bias are listed and divided based on their control strategies in Table 3-1.

Table 3-1 MV Boost List for External Bias
Main Control Strategy Control Strategy at Light Load Devices Supporting External Bias
Fixed Frequency Modulation Pulse Skipping Mode TPS61175(1), TPS61170
Pulse Frequency Modulation TPS61178(2)
Forced PWM Mode TPS61175(1), TPS611781(2), TPS61080, TPS61081
Quasi-Constant Frequency Modulation Pulse Skipping Mode TPS61086, TPS61046, TLV61046a, TLV61048, TPS61085
Pulse Frequency Modulation TPS61288, TPS61088, TPS61089
Forced PWM Mode TPS610891
Pulse Frequency Modulation Pulse Frequency Modulation TPS61045, TPS61040, TPS61041, TPS61096a
(1) The TPS61175 works in forced PWM mode when the on time is longer than minimum (60 ns), and enters pulse skipping mode when on time is clamped to minimum.
(2) Do not use the isolation MOSFET of the TPS61178 and TPS611781.

Take the TPS61089 as an example. Figure 3-1, Figure 3-2, Figure 3-3, and Figure 3-4 show the main waveforms with external bias and without external bias in CCM and DCM, respectively. When power Vin equals to signal Vin, there is no difference for the device so the waveforms are the same. This assures that the TPS61089 can be used in external bias applications.

GUID-20211008-SS0I-GVG9-BNFQ-PPRVVQSHP2BS-low.gif
Power Vin = 3.6 V, Vo = 9 V, Io = 1 A
Figure 3-1 TPS61089 CCM Waveforms Without External Bias
GUID-20211008-SS0I-H93T-CGPZ-BBLBTC3K98SV-low.gif
Power Vin = Signal Vin = 3.6 V, Vo = 9 V, Io = 1 A
Figure 3-2 TPS61089 CCM Waveforms With External Bias
GUID-20211008-SS0I-JXVJ-BBBQ-KTXXTTF84JG2-low.gif
Power Vin = 3.6 V, Vo = 9 V, Io = 0.2 A
Figure 3-3 TPS61089 DCM Waveforms Without External Bias
GUID-20211008-SS0I-6PRQ-BFFV-RFTXDNQWDX91-low.gif
Power Vin = Signal Vin = 3.6 V, Vo = 9 V, Io = 0.2 A
Figure 3-4 TPS61089 DCM Waveforms With External Bias

With external bias, the input voltage range of the TPS61089 can be extended as previously analyzed. Figure 3-5 shows the waveforms of the TPS61089 when the signal Vin is 3.6 V while the power Vin is only 1.5 V. Compared with the 2.7-V minimum input voltage for a typical application, the device can work with much lower input voltage as long as the current limit is not reached.

GUID-20211008-SS0I-TR5R-LWVS-SFKSR0VG8PP7-low.gif Figure 3-5 TPS61089 Power Vin = 1.5 V, Signal Vin = 3.6 V, Vo = 9 V, Io = 1 A